The 3rd movie is so radically different than the original series that there's probably nothing from it that can be applied to the original series. There are a lot of in-world mechanics that seemed to have changed, for example:
- Angels all explode into blood
- Souls of the pilot's mothers in their Evas (Eva-05, Eva-02)
- Impact mechanics are different, the (near) 3rd Impact being generated by Eva-01 and Rei
- 4th Impact initiated by 2 spears and a double Eva-13
- There's a new set of Angels called the "Nemesis series"
Additionally, aside from Misato and Shinji's backstories which seem to be similar enough to the TV series, it's either unclear or outright different (Asuka) for the histories of the other characters.
There could be small arguments made that can be applied to the original TV series. For example, Bardiel is clearly inside the entry plug in the 2nd movie, so one can argue that this can be applied to Bardiel in the TV series which leaves things more vague. Or in the new movies it's revealed that the S-DAT player once belonged to Gendo and Shinji values it because it was his father's. But for the most part, I don't think there's going to be that many new things revealed about the original series thanks to the new movies.