I'll go in order starting with
Unit 00:
The only glimpse we get of the real Unit 00 is at the end of 1.0, when part of its armor has been burned off by Ramiel's positron beam. We can see the ends of its hands and some swollen, bubbling flesh in the cracks of the knee joints:
It's very difficult to tell because of the lighting and the burn damage, but it appears to have brown flesh like the original Unit 00 did. Curiously, it doesn't have the knuckle dusters embedded in its hands here.
Unit 01:
Unit 01 appears without its helmet very briefly during the Operation Yashima preparations
It's bandaged and submerged in red LCL, so we don't get any insight into the color of its eyes or head, but the overall profile looks very similar to the NGE Unit 01. It looks like the sclera might be white instead of green this time.
The teeth aren't visible here, but we get several good looks at them in the next movie:
They very in number and shape from shot to shot, but we can see that it has a deep, u-shaped mouth and that the teeth are red for some reason. There's a hint of what looks like gum visible between the teeth and the helmet.
The skin this Unit 01's hands and chests is a pale white color, pretty close to human tone. It has clearly defined fingernails and a single large red core set in its chest. It lacks the two smaller cores the other Unit 01 has:
In this next shot and the first shot of the teeth, you can see the edge of Unit 01's mouth, and it's black:
I'm not sure what to make of this. Most of the Evas do wear a black under-armor suit but it usually stops at the neck and doesn't cover the face. Eva 13 has this too, so I'm not sure if it's part of the suit or if Unit 01 possibly has two tone white and black skin instead of the light/dark brown skin it had in NGE.
In the first pseudo-evolved form, Unit 01's eyes glow pure red and it occasionally emits fierce red light from its mouth:
It seems like the glowing mouth might be related to the eye beams. It only glows right before or right after Unit 01 uses that power.
Just before entering the second phase, the Eva's body becomes translucent, showing off its nervous system and glowing heart:
The second phase transforms it into a blazing reddish-purple energy being with two cores and a third eye. It's still translucent, and it manifests at least 12 wings of light from the region of its two cores:
*Update*: An infographic pops up on Maya's screen when Unit 01 is fighting Sachiel that shows us two interesting tidbits about the Eva:
Unit 01's blood type is blue derivative. Blue **A' vs Sachiel's blue 04. The other is the origin of the Eva's AT Field: it's being generated by the entry plug and the core unit, where the Eva's human elements reside. Just speculation, but I think this might explain why Unit 01 can generate an AT Field but Unit 13 can't. It's been modified by Yui's presence in the core as a "pilot interface."
Halo: Unit 01's halo has a broad ring that's ragged on the inner and outer edges. It's predominantly white, but there are very light splashes of color throughout the ring:
After Unit 01 takes over as the power source of Wunder, the ship manifests two concentric halos with extremely similar structure and coloration:
Unit 02:
Unit 02 only sheds its armor in its two beast forms, which both alter its anatomy quite a lot. This ability combined with the presence of the limiter rods makes it unclear what the Eva "normally" looks like. Is it supposed to be a human-shaped? Is it really a cat?
The first form extends the Eva's limbs and neck, and the torso grows thicker and longer:
And just like End of Eva, there's no hint of a core on the Eva's chest. We know it has one and the housing unit hangs out the Eva's remains after it self-destructs. It seems like it should be right between the red v-plate and the pattern on the chest.
Unit 02 rips its helmet apart, revealing a huge mouth full of needle-like teeth that appear to be embedded on the outside of the mouth. It's been suggested that the "teeth" are actually staples or sutures holding the mouth shut since the Eva struggles to open its mouth, but I think that's because it has to break the lower jaw on the helmet:
You can also see grey flesh on the back of its neck. Unlike the NGE Unit 02, this one has red blood.
The Unit 02 in 3.0 looks completely different from this one. It still has grey flesh, but the mouth is much more broad and shallow, there are fewer teeth and they're now proper teeth instead of those skinny needle teeth from 2.0. It's actually kinda pug-faced and lumpy now:
The lumps of its spine are visible on its back:
*Update*: Here's a better look at this beast form:
You can see how shallow its skull is in that profile shot. Much shorter and more human like than the normal elongated, narrow Eva skull.
Code 777 throws the human body type to the wind and transforms Unit 02 into a long-bodied sabertooth cat, complete with paws and a tail. The limiters break off of its body and it gains more defined musculature, especially around the jaws. Still no hint of a core, though:
We get a really good look at its innards after it explodes, including what I believe is the core housing ring dangling from the bottom of the chest right next to the spine.
*Update*: At Reichu's suggestion, I collected some images and art of Unit 02 when its core is being removed for containment:
The Eva's chest plate has been removed. The chest itself is blacked out and shadowed, so we can't see where the core actually sits, but judging by the position of the UFO catcher claw holding the core, we can infer that the core would be sandwiched between the pectorals and the first abdominal plate. It's a little lower than Unit 01's core, but right where you'd expect an Eva's core to be.
This scene shows us another interesting fact: a normal Eva's body does not collapse when the core is removed or destroyed like an Angel's does. Unit 02's body is still somewhat intact after it explodes, Unit 03 leaves its bloody gibs scattered all over town, and Unit 00's leg stumps spew blood but don't seem to explode.
Unit 03:
We get a nice closeup of Unit 03's eyes as it flips toward Unit 01, showing the three smaller circles within the iris that were present in the old Evas.
Unit 01 crushes its head open during its brutal dismemberment, and we get some fragmentary glimpses at the Eva's true colors. The sclerae and irises of its eyes are both green. It also has teeth and a tongue which aren't visible when its mouth is open for some reason. The teeth are embedded in a charcoal colored piece of flesh. Perhaps they're embedded on the outside of the mouth like Unit 02? Gore warning:
The Eva grows an extra set of arms out of its shoulders and has extendable, rubbery limbs as a result of its infection by the 9th Angel.
Mark.04A:
4A takes the form of a saucer with two cores on the under side and four pylons mounted on the top:
4A has a trait not seen in the other Mark.04 units: in the profile shots, it appears to have a normal Evangelion torso sticking out of the bottom, complete with legs that taper into two blades.
The Eva torso is actually mirrored on both sides. The front and back have identical chevron plates and pelvic boots, with no spinal armor seen in the normal Eva Units. It can even rotate a full 360 degrees with no trouble.
The "thighs" are cut in half. The insides are flat and conceal the energy shotgun weapon the Eva uses to destroy Unit 02's AESS shield. The bladed legs can split in half at the knees to form four spidery legs.
Mari is able to destroy them with a single shot fired lengthwise through the saucer section, which causes the Eva to detonate in a pink explosion:
A couple more interesting notes: 4A is able to mask its location with a cloaking cocoon like 4C, although we never get to see this in action:
They can fly very, very quickly by propelling themselves with a layered octagonal field that's similar to an AT Field. This field is primarily blue-green and lacks the inner rings seen in AT Fields. Here's a nice comparison against Unit 02:
Wille appears to be using several stripped down 4As as the N2 Reactor power sources for their ships. The armor on the pylons and saucer havs been stripped away, revealing the mechanical structures underneath. The torsos have been removed and the saucer sections are held up on scaffolding. You can see three on the left and two more in the lower right:
Mark.04B:
4B is a saucer with two pylons, one core, and no apparent appendages. It's able to deploy long reflective ribbons from its housing on the tesseract, and the saucer can move along them at high speeds, but it isn't attached by anything. When Unit 01's Buster Beam shreds the ribbons, the saucer goes flying off the end into space.
Unlike the 4A, 4B doesn't have any visible means of propulsion. It just slides along the ribbons like a top. It's never mentioned as having a cloaking cocoon, but the box it hides in serves the same purpose. Unit 02 never detects it until it's ready to attack.
When the Eva kicks into action, Magi Achiral identifies it as a pattern blue, or specifically, "Blood Type≈Blue." The 4Cs are also pattern blue, and it's probably safe to assume the 4As are as well. Possibly related to Unit 01's unusual blood type?
After getting bisected by Unit 01, 4B's body erupts into a shower of blood like an Angel, complete with cross and rainbow.
Mark.04C:
Code 4C's saucer section is blown open by the Wunder's main guns, showing us that the inside is apparently just huge disc of core, very similar to the Mark.09:
It has several smaller cores embedded on the outside of the saucer and wavy filament-like arms, but they don't appear to correspond with anything inside the Eva's structure. Upon death, they explode into crosses and rainbows.
Mark.06:
Our best view of an unarmored Eva yet! Mark.06 has a lean, tightly muscled body, a lumpy, egg-shaped head with little ears, and dark greenish grey flesh:
The ears are a curious detail. It's the only Eva we've ever seen that has external ears and the only other giant besides Lilith. Adam doesn't seem to have them either. There's big lump in its suit just under the chest which is most likely the core, and it has a mask stitched to its face. There are two holes in the mask of unknown origin. Could they be a stab wound from a Spear of Longinus?
The Eva's eyes are covered by the mask and by a visor, but the official artwork and preview at the end show that it has two:
The uncovered Eva is wearing a greenish body suit with ribs along the shoulders. After Unit 01 is heavily damaged by Sahaquiel later in the film, you can see a similar suit through the hole in the shoulder armor:
*Update*:
Halo: Mark.06's halo in 2.0 is small, thin and wispy, more solid on the outside edge and turning ragged torward the middle. It's purple and white:
The Eva's corpse farts out a similar halo in 3.0. There's more color variance and it quickly expands and dissipates, but the composition of the ring is practically the same:
In the next post, Reichu mentions the Eva's helmet having jaw articulation, a strange feature when it appears to be wearing that Seele mask under the helmet. This was first revealed in the action figures, but you can just barely see it in action in 3.0. As the 12th Angel thrashes around in Mark.06's empty armor, you can see the jaw armor tremble and move up and down just a little bit, like the mouth is trying to open:
The Eva's visor in that shot is filled with the red glowing clusters that make up the 12th Angel's body. Concept art from the 2.0 CRC shows the Eva having another layer of armor underneath the visor that forms eye holes. Further evidence that the 3.0 Mark.06 is nothing but a hollowed out husk:
In the very first image in this section, you can see that Mark.06 is hooked up to an IV that's labelled "BTB." The most obvious breakdown for that acronym is "blood type blue." Is Seele giving the Eva a transfusion of Angel blood? There's certainly enough of it laying around after Sachiel and Shamshel are defeated.
Mark.09/The Vessel of the Adams:
Hoo boy. It looks like a big-eyed Unit 00 at first, but the weirdness kicks in when Mari caps it in the skull:
Two more shots take the head completely off. A bit of blood sprays, bits of the helmet go flying, and the eyeball briefly dangles from a cable or something, but there's still nothing organic that we can see:
*Update*: Reichu helpfully pointed out that Mark.09 does have a lower jaw and tongue visible for just a few frames as its head is exploding:
We also get a few good looks at its neck stump later on in the movie, and there aren't any bones or meat visible. It's just a flat plate with a hole:
Near the end, it sprouts a new head with a horn and twelve glowing circular eyes. It has a large mouth full of fangs and a triangular tongue:
It's not clear if this new head is what the Vessel's head really looks like, or if it's wearing some kind of helmet.
The Vessel is able to change the color of its body. It's originally yellow-orange, white and grey, but it turns black with a bright red under-armor layer after flashing blue
It sprouts glowing blue tentacles from its legs that are able to infect and hijack the Wunder's machinery. They look similar to the blue gel that made up Bardiel's core without the weird staples. The color and effect are different from the blue color shift above, though.
Here we get a good look at the Vessel's body under the abdominal plate. There's Seele's mask-plate protecting the core, the core itself, and the Eva's body, which is a huge lump of core with a vertical streaking pattern in it.
Why does it need the protective plate or another core when it's already made of the stuff? Asuka shoots five rounds of Anti-Eva ammo right into the core through the entry plug chute. The Vessel just reforms itself with no damage. It even looks like it's made of a bunch of cores that are tightly crammed together into an Eva-shape:
*Update*:
Halo: Mark.09's halo is very broad and slightly thin. The ring is very tight and rainbow colored, with a bit of fraying at the edges on the outside and inside:
It's not as bright or intense, but the halo's color and effects are very similar to Eva 13's smaller inner halo.
Unit 13:
Unit 13 is the first Eva explicitly confirmed to be an Adam, but it has two features we don't see on any of the four Adams in the flashback: four eyes and four arms. Unlike Unit 02's four eyes, those are right beside each other, so close that they press into each other when the Eva begins to awaken:
It's very possible these were added to the Adam by Nerv/Seele while it was being built, and that it would normally have only two of each. Some people have speculated that Unit 13 is actually the two missing Adams fused or grafted together somehow. Maybe it's a fifth Adam that hasn't appeared before. We've only seen evidence of four, but the Vessel wasn't exactly foreshadowed either.
Like Unit 01, Unit 13's teeth appear to be set in gums within the mouth. The teeth are large, white, diamond-shaped fangs with two wider incisors in the front.
You can see the black corners of the mouth in this shot, too. Flesh? Suit?
As it transitions into its awakened form, the Eva blows off its pylons and sprouts blocky red protrusions from its shoulders that form into smooth wing-like structures:
The blocks look very similar to core but lack the distinctive glistening pattern. They're just solid red. The blocks are also kind of similar to the black structures that make up the 12th Angel.
There's an x-shaped indentation in Unit 13's chest plate where the lower arms normally rest. It glows a furious red color when the Eva collapses the giant Lilith fetus into a core and then stops. It's somewhat similar to Unit 01's glowing mouth in that regard.
One last interesting detail: Unit 13 does not appear to have the usual mechanical spinal socket that the other Evas do. Instead the entry plugs are inserted into pools of purple light:
The normal sound effects play when the plugs catch and lock into place, but there's never any visible machinery.
*Update*:
Halo: Unit 13 has two intense halos oriented behind it instead of over the head like the other Evas. They're both bright, tightly focused and spin very quickly. They're both rainbow colored in some shots, but in others the inner one is rainbow colored and the outer one is predominantly pink.
Unit Null
A new Eva of dubious canon status coming courtesy of the Animator Expo. Unit Null is very mysterious, but the concept artists were kind enough to provide us with a nice view of its head:
Seems to have the normal narrow Eva skull. The forehead has markings that could indicate scarring or the pseudo-Angel mask NGE Units 01 and 02 had. The chin is longer and more pointed than other Evas we've seen and it has a downturned, frowny sort of mouth. Null appears to have had its eyes removed; there are scars where they should be. Accordingly, the Eva's helmet has no eye holes, just glowing blue lights encircling the area the eyes should be. It's somehow able to see even without any eyeballs. Perhaps it's able to see through the cameras mounted on its body, or through whatever means the Vessel uses.
Adams?
Lastly, there are these four weirdos who briefly appear in Until you come to me.
They seem like decent candidates for the Adams circa Second Impact. They have thin, emaciated looking bodies with protruding spines and rib-like structures on their chests. They have the trademark creepy glowing Eva eye, but green as opposed to the red ones we've seen so far. The teeth are very similar to Unit 01's, but they're white and embedded on the outside of the mouth with no visible gums. The color's off in this scene, but it looks like they have light brown skin. That guy in the back doesn't seem to have a core, either.
They do somewhat resemble Unit 01 aside from the external teeth, but Mark.06 doesn't look anything like this and the mouths and eyes are all wrong for Unit 13. They're much more thin and wiry than NGE Adam and it had a rounded cranium without that protrusion at the back of the skull. Even if they're not the Adams, it's still a treat to get such a clear look at these creatures.
Eva Simulator
This hideous thing appears in 1.0 as the new Eva test/simulation body. It looks like a stripped down Eva skull and spine with some questionably organic parts. The spine is a mechanical Eva spine and is outfitted with the usual entry plug mechanism to hold the simulation plug. It doesn't have a core at all. Instead the entry plug connects to a gasmask-like apparatus that is in turn connected to the head where the mouth would be. NERV has cores mounted in the floor for harmonics tests in 2.0, so I can't imagine why this doesn't have one.
The head also looks like it's mostly mechanical. The robotic eyes swivel rapidly in all directions and the head is interlaced with pink things that could be either cables or muscle tissue. The pink thing in the throat pulsates regularly and I think that is organic, but I'm not entirely sure what it is. But when the head is viewed from above...
There's a brain in there! It could be an artificial brain like the MAGI used in NGE, but that is definitely a brain. The rest of the chamber is just made up of wires and support cables connected to the head and spine.
It's fascinating how much diversity there is between the Rebuild Evas. None of them look very similar at all except for Units 01 and 13.