I could potentially help with a final version of/when it comes to that.
I worry the Rey backstory stuff could be too complicated. A positive of this version would be that you could keep the movie as close to the theatrical version as possible but still make Rey not a Palpatine, or at least not one by blood.
On the other hand, you still have some retroactive issues, like her parents having a change of heart and being good or whatever.
I like this quote of your’s Nev:
We already know from the OT that having an evil relative doesn’t matter, so it doesn’t really matter if Rey is a Palpatine or not. But what does matter is a person’s training and their actions, especially in regard to the Dark Side.
This is why I do sort of keep coming back to “Rey killed her parents”. It doesn’t really contradict the last 2 films, and it stills makes it so Rey doesn’t have an important backstory. Plus her own actions in the past define her potential destiny, not her parentage. Makes it different, but not convoluted. Your general audience member would understand it.
I think making the Sith Throne a “secret” that doesn’t really get spelled out until the climax could potentially leave the audience confused. I think it is a safer bet to make it clear early on in the film that the throne is the source of Palpatine’s power to cheat death. Then, at the end of the film, you could decide how you want to clarify how Rey decides to destroy it. The voices of the Jedi tell her, internal monologue, something. Does Rey really need a connection to Palpatine beyond the power he offers? It’s not like Rey briefly being his adopted child is going to make the audience think that she actually might join him more than any other option.
I guess it does give you the angle of “Rey has been trained” if you want to try and address that question.
So, putting simply, her backstory would be this: Rey’s parents were followers of Palpatine. They gave up Rey to be trained as a Sith and eventually be Palpatine’s heir/apprentice, but they had a change of heart and ran away with her. They hid her, then got caught and killed. The trauma of Rey’s abandonment made her forget everything.
It could be interesting if Palpatine tried to manipulate her, and say that her parents took her away from having a better life than they did. Hmm.
Speaking of Rey killing her parents, didn’t Palpatine also kill his own parents in Legends?
EDIT: I will say the toughest thing about the Rey Palpatine/Nobody stuff is deciding on an angle and the dialogue. If some kind of consensus could be made on that, I don’t think it would be so hard to actually make the scenes with the dialogue. Just need some brainstorming to come up with something.