I really hope its not that, because it's like, the only other thing your mind comes up with after "not Lisa". If it's not Lisa tbh I don't think it should be a twist at all. Just some other poor fucker Umbrella fucked with.

If it’s a new poor soul and we got snippets of lore from their before times/mid infection like we did with Lisa in RE1 remake I think that’d be the perfect way to have it both be a throwback and tell the story in a way that encourages exploration

Coming from someone who’s new to the series and has only played up to CV so far and assuming that you’re talking about Alyssa being the stalker enemy: I think it could work as a neat inversion of Lisa Trevor. Almost like history is repeating itself all these years after the Mansion incident. Plus-

-it gives Grace a more personal connection to what happened at Raccoon City; iirc she would have been born after the event, so she wouldn’t have any trauma from it or any ties to Umbrella the same way that someone like Leon would. But-

-watching her mother get murdered in front of her, followed by her finding out that her mother was turned into a monster that’s now after her, all caused by or as a result of Umbrella’s wrongdoings? That’d definitely make things much more personal for her. But also idk those’re just my thoughts