Well, following what I proposed yesterday I was thinking that if you really wanted that Rey was the daughter of some preexisting but very obscure and unknown characters; you could have Laze Loneozner and Camie Marstrap (Luke’s friends from the deleted scenes of ANH) as her parents (this would all be headcanon since I don’t know how to incorporate that in the films in an organic way)
Toying again in my head with the idea of making Rey’s plot twist being that she killed her master instead of Rey being Palpatine’s granddaughter, I thought:
Would you like the idea that Rey’s master (her mother in the actual film) was Luke’s former apprentice and Luke gived her lightsaber to Rey instead of Leia’s lightsaber during Episode IX?
I thought that it might be doable but would make Leia’s role in Episode IX even smaller than it already is
I also thought that the idea of Rey having a Jedi master would raise several questions to the general audience like: Why she doesn’t appear either as a voice or a ghost through the entire trilogy?