I think that Leia dying of healing ben is the best case scenario without reshooting the scene
But if we had infinite financial resources
Floating palpatine is a Hologram projected from a Holocron, not a physical clone, but he wants a physical vessel through possession
Rey leaves Kylo to die, Leia heals Kylo, rey goes to ach-too, Kylo tries to confront the emperor and kills the KOR, Kylo is captured by the imperial guards, palpatine ties Kylo up and tempts Rey to kill him, Rey spares Kylo, Kylo and Rey are force drained by the Holocron and becomes a physical person
Palpatine floating in the air due to a harness gave me the hologram idea
Wish these guys go faster