I don’t believe that it is stated or implied that anything that happens in the Ter’angreal is true. Certainly it doesn’t make sense that Aginor would have been around to assault Nynaeve at some point in her past. It does seem to be the case that the three rings might have some element of past, present, and future, but that doesn’t seem to align as well with the things that Egwene sees. It’s also apparent that the things seen are associated with fears of the candidate. It may be that this is a representation of a past fear that Nynaeve had in order for her to face it and overcome it. So not necessarily something that happened but perhaps something that she was afraid of. It isn’t really ever made fully clear, but I don’t think it’s meant to be the case that Nynaeve was actually assaulted in the past.

The three oaths are generally grounded by the oathgiver’s grasp on reality. It is at least implied that the oaths can effectively be broken by someone able to manipulate her own view of reality to the point that she doesn’t believe she is violating the oaths. Verin is able to somewhat defeat the BA oaths by literally interpreting “hour of her death” when it might have been intended figuratively. Of course, the BA oaths is worded somewhat unnecessarily poetically. Or maybe it was a backdoor that some early reluctant BA member built in. That said, RJ treads very lightly in this area and I think that is for the best as a story needs to feel like it has rules and that breaking rules at least has serious consequences.

This is a key to enjoying wheel of time in my opinion. You aren’t meant to like the protagonists all the time. They get more likable towards the end.

That’s actually what happens in the book, too. Perrin and Elyas have this discussion, right after the Ravens pursuit. It would hardly have been adapting. Just acting out a scene from the book as written.

It’s stated that GC is always significantly older than Birgitte. When she is ripped out, this is not a normal life as she appears as an adult with an understanding of who she is and remembers some of her past lives. She dies and will then be able to be born normally, although presumably not for years at GC is only a baby at the end of the series.

Mat doesn’t have any POVs until book 3. Not including the ravens prologue (which wasn’t part of the original publication) Rand and Perrin have almost all of the POVs in book 1. Nynaeve has a few and Moraine has a paragraph at the end of the book. But if you are arguing that we need inner monologues to understand early Mat or Egwene, you aren’t being fair.