That would take me out of both of those respective scenes. I think it’s gotta be a voice for 2 reasons:

Dispell the notion that Palps is literally every voice in his head. It’s just him manipulating Kylo.
If he ever took a corporeal form then Kylo would certainly try to attack him, or at the very least try to shoo him away, even if that wouldn’t do anything. With just the voice, he’s more powerless.

I think the concept I’ve got in my thread works because it’s just after a devastating moment: Chewie’s “death”. We’ve just seen Rey’s reaction to that. It makes sense, structurally, to then watch Kylo battling with his conscience after such a thing (at least, that’s what the audience is meant to believe in that moment). I can think of no better candidate for him to have such a conversation with in that time than Luke.

Ultimately, this idea isn’t going to be in this edit. That’s fine. We can drop it. I’m gonna make sure it’s given proper attention in my thread.