It's unknown how the roof is gonna work
Luffy has been ignoring momma all arc so maybe he ignore her again but there's the barrier feat. Luffy failed to tank big mom's slap in udon using the haki barrier and it feels like Luffy has to manage to do this at some point.
So what if, Luffy fights them both? Like no joke. They actually tag team the man together and he doesn't go down immediately. There's two feats hanging in the air. Luffy has to damage kaido and Luffy has to tank a slap from momma. He might actually do both in a 2v1.
This would be awesome as chapter 1000.
Then for chapter 1001 when Luffy is about to get stomped, kid law and zoro make it there and they organise themselves somehow to fight both yonko.