It's 12 chapters. Once the flames on the seraphims go out then they're gonna get destroyed so that's not going to take up more than 3 chapters.
Tf you mean "York, Vegapunks resolutions" that makes no sense.
Kuma's backstory isn't even 100% guaranteed and even if it was it's not gonna take up more than 3 chapters.
So that takes up 6 chapters and we have 6 left for the Egghead incident which is more than enough.