Hi!
Here am I, past midnight with several backlogs in
several things, but cooking up weird theories that just seemed too coincidental... Or ARE THEY!?
Ok, hear me out...
Given that:
One of the things stablished in NGE is the inherent need of a soul for producing an AT Field (Evas, humans, Seeds of Life and arguably, Angels).
All Evangelions need a soul, which
optimally should belong to the designated pilot's mother (Eva 00 being the exception).
Souls can be recovered, captured and stored for significant amounts of time. Nothing says they can't be also transported to be implanted in a new host.
Souless entities can exist, albeit certain measures should be taken to keep it from collapsing while awaiting for a soul (e.g. the Reiquarium)
Late in the series it is stablished that SEELE was building the Mass Production Evas, and had been doing so for a long time.
While it is plausible they simply used one of the many souls they had in storage (i.e. Shinji's classmate's mothers), I think it is possible they had other plans:
Enter the souls of the Angels
Would it have been possible for SEELE to capture the souls of the defeated Angels and use them to complete the MP Evas?
They do say their original goal was for 12 units, but had to settle down to 9. But why was that? No time, no money?
How about, they missed the oportunity to capture the soul?
Being in the inmediate vicinity is not necesary, but it certainly helps. Also, some sort of ghost-busting equipment would have been readied to isolate and contain a soul. When I see an Angel list I notice that at most, only 9 of the Angels souls could have been readily salvaged:
Sachiel: walked slowly to Tokio-3, they had the time to set any equipment.
Shamshel: wriggled slowly.
Ramiel: floated slowly AND took it's sweet time to enter.
Gaghiel:
lost in the middle of the sea.
Israfel: they had a freakin' week to set anything.
Sandalphon: finders keepers!
Matarael: had time.
Sahaquiel:
didn't even know where it would land for sure. And setting anything up while coordinating 3 Evas seem like too much.
Ireul:
an interesting case. Gendo actively denies it's existence. More on that below.
Leliel: the thing was floating over their head for quite some time.
Bardiel: surely they noticed it coming.
Zeruel:
with all the destruction and mayhem, it is possible they missed the chance on this one. Arael:
Lost in space. Along with the Lance!Armisael: no excuses here. Sure, they lost and Eva. And the city.
Tabris:
Soul arguably went to Gendo's tumorous hand.
In total, it is possible they only managed to salvage 9 of the Angel souls. Maybe 12 was their original target, but had to settle for less after Ireul.
Why after Ireul? Because by this point SEELE starts to get suspicious of Gendo: he goes to great lenghts to dismiss the idea as nonsense.
What if one of Gendo's job was to get the souls for the MP Evas, get them ready and ship them to wherever SEELE were building the MP units. All the Angels were sure to attack in Gendo's proximity.
Gendo also knew the MP Evas would probably be used against him in the end, so why give SEELE the things they needed? He could fail once, or twice... Or five times. All with masterfully crafted excuses.
This brings me to the next point: the pilot of the MP Evas (or lack thereof).
Enter the Kaworu Dummy Plug.
Why creating an entirely different Dummy for these Evas?
I think there's more to the Dummy than Ritsuko's say that it "mimics thought patterns to trick the Eva into believing there's a pilot".
My theory: they used Kaworu Dummies because it was necessary to better communicate with the Angel souls.
It makes sense that a Lilith-based soul (Rei) be used to communicate with another Lilith-based soul (the Eva's core).
On that logic, why use an Adam-based soul to imitate a Lilith-based soul? We do see that direct communication between entities is complicated, blotchy at best, mind-shattering-traumatic at worst (Leliel, Arael and Armisael).
Isn't it better to use a Dummy based on Adam's literal soul to control a bunch of Evas with an Adam-based soul in them?
In short: SEELE used the souls of the defeated Angels to power the MP Evangelions and used another Adam-based soul (Kaworu) to create a Dummy plug that could communicate seamlessly with their Evas.