-also Rei Q and Rei in the Mark X are reminding me a bit of Elpeo Ple in Double Zeta
This might seems like a heretical statement here but both EoE and Q have relatively straightforward/simple scenarios (that's in no way a criticism, it's a large part of their strength/beauty as films) where if you jotted down the actual action that happens it's quite straight forward, there's isn't a convulted or complex narrative scheme (but that's not to say it isn't tightly plotted) but there are mountains of detail, character nuances and interpretation which will take years to untangle on top.
I feel Shin Eva will probably a fairly straightforward structure something like
-Paris AVANT
-Until you come to me sequence of the Pilots wandering through the Third Impact landscape
-reach a Lilin settlement or are collected by the Wunder (back from Paris) and go to a Lilin city (I remember there was a Q and A with Anno where he talked about the alt Eva film that was planned in the late 90s that had a scenario similar to Attack on Titan, esp with Humanity sheltering in one city led to by a giant bridge, and that ideas from it might be used in the final film)
-they launch the big assault on Neo-Nerv/the Black Moon where they get to do a big Gundam/Yamato style finale against the enemy base, like A Baoa Qu, Neo Zeon's Axis, Gamilas, Gatlantis, Dezarium or obvs Red Noah in Nadia
and then all guesses are out the window when it gets to Final Impact or whatever world Shinji feels he can exist in.
Thinking of the preview they played before the screening of AVANT 1, it seems 'Why do you pilot Eva?' is one of the central pillars of Rebuild. Like in Q where Shinji has to be shown the outside world and given hope by Kaworu that he can fix things with the spears, he'll need a key moment of absolute crisis (like Yui breaking through the bakelite and hearing Asuka defeated by the MP Evas) to get back in the entry plug.