I don’t think that Kylo should tell Rey that Palpatine is lying to her, or giving her visions. I think that can be implied, however, if the visions first appear in some fragmented form when Kylo interacts with the Vader helmet and they share a vision, basically like the theatrical version of that scene.
In the Kylo quarters fight, it could be that Kylo is surprised at the new version of Rey’s past that he has seen, since he didn’t see that in her memories before, but I don’t think he should outright suggest that this is a device of Palpatine. Again, if Rey knows for sure that Palpatine is lying about her past, then she can easily discard it. So that interpretation should remain plausible but unconfirmed for the entire runtime, and the story should be about Rey choosing which story to believe.
I agree that Rey believing the story to be true should be held for as long as possible to maintain story tension. I just wonder if there’s a way to show that Kylo is confused by this new vision to better sell the idea. I might take a crack at wording the hangar scene to frame it so that the Palpatine story is just something Kylo heard, not confirming or denying anything, only to then reiterate all he thinks is important is the Dyad he and Rey form.
For this to be communicated, we would need to alter the D-O scene and maybe give D-O some new lines if we want to be fancy, in order to prevent confirmation of Rey Palpatine. Luke’s line of ‘Because you’re a Palpatine’ doesn’t actually need to change, since it could merely be that he is giving voice to her greatest fear, not confirming it. His next line could be ‘Leia sensed your fear.’
It would depend on what lines D-O would have, but the thread seems to be heading in the right direction so far.
The only other thing that is needed to pull this off is to give Finn a line where he pushes back against Palpatine’s story and tells Rey that she ultimately must choose her destiny, not the Emperor. For this, I think it would be interesting if we used this opportunity to give Finn some closure to his character arc as well. From a practical perspective, Finn would want to get to Rey in order to convey his doubt to her, which means that his mission at the end of the film would be similar to the one in TFA: he is involved in a Resistance attack but has the ulterior motive of wanting only to find Rey. However, he ultimately chooses not to find Rey and instead chooses to sacrifice himself for the Resistance, knowing that this time his sacrifice will not be in vain…
Removing the voices of the Jedi that Rey didn’t know in life will emphasize that she has rejected her desire to find belonging in the past, and will choose instead to take Finn’s advice and rely on the strength of her friends for her future. Burying the old lightsabers in the homestead is final confirmation of her new resolve.
Ooh, I really love this idea, since I think the only film in the Skywalker Saga where the final battle is a rescue mission is Phantom Menace? I think the only issue then is a lack of reaction shots of Finn sensing Rey’s death & resurrection, but I could just be overthinking it.