I don’t think that’s what Hal was saying. It’s a given that “Just Rey” only works if she’s Palpatine’s progeny. What Hal’s saying is he thinks “Just Rey” needs to be specifically set up by the explicit use of the name “Rey Palpatine” at some point during the movie, which I don’t think is necessary.

But yes, the “Just Rey” ending only works if she’s a Palpatine, because it’s her specifically choosing to forge her own path and not aligning herself with her actual family name (Palpatine) or her “adopted family” name (Skywalker).

In a Rey Nobody edit, you’d have to do something else with that scene, I think. If you even use it.