With the “Rey killed your parents” idea, if you could change Luke’s line, “Because you’re a Palpatine” with “Because of your parents.” or something like that, with maybe slight alterations to his mouth movements, you wouldn’t have to change anything else about that scene.

Also, if you could give Luke a new offscreen lines before “Some things are stronger than blood” you could recontextualize that line to be about Rey’s bond with Leia being very close, rather than it being about her blood relation to Palpatine.

Also, this might be a bad idea, but I wondered if a Rey Nobody edit could still work with the Emperor still referring to Rey as Empress Palpatine. Like, Palpatine would know Rey’s quest for belonging and family, so it could be his way of saying, “the belonging you seek is with me”. But, it could also be a way for Rey Palpatine to still be hinted at for those who like that. Kind of how Deckard being a human or replicant is left ambiguous. Anyway, just a thought.