Dont think he will kill Kaido, but for sure he will cut Kaido with Ame-no-Habakiri in the place Oden gave Kaido the scar, there are strong hints on Oden swords inheriting his Will/Haki, even Kaido feel it with Enma, so with mix of Oden and his own CoC he will be able to damange Kaido, much like Zoro, and them Luffy will hit the open wound, thats how probably Kaido will be beat, but i dont think Kaido will die, doubt that Oda will give Kaido what he want. Probably he will be taken by CP0/SSG for his powers of Oni/Dragon to be used in some weapon manafacture for the Final War.
Belive that Hiyori is with Ame-no-Habakiri and will use it to cut Orochi last head, them she will give it to Momo, thats when we will see Momo 28y human form. Probably she is the shadow we have seen and will represent the peacock/pheasant of the Momotaro legend, like Luffy is the monkey, Yamato is the dog and Momo is Momotaro himself, all the four being people who have the Inherited Will of Oden. The four colaborating to beat Kaido.