I’ve always interpreted the ghosts holding up their hands as them using the Force to keep Palpatine’s spirit trapped within his body. I’m not sure how we can make that more clear. Maybe a VFX change around Palpy? As for your other point, the reason Kylo needs to be the initial target of Palpatine is because it doesn’t make much sense for him to still want to kill Rey at this point, otherwise. Kylo is already closer to the dark, a more suitable host. He’s spent the past 20 years twisting his mind with the voices in his head. It’s why he mentions that the “Princess of Alderaan has disrupted [his] plan” after Kylo becomes Ben.

The only other complaint I have is that it might not be extremely clear Rey’s mother did give birth to her, but isn’t genetically related. We’re trying to avoid the false impression that they simply adopted a clone of Palps, because the Sith cult could do that themselves.

EDIT: I think I also preferred that they “couldn’t escape the shadow of the Sith.” Destiny doesn’t usually relate to death.