Smoker, Tashigi, Vegapunk, Kuma, Bonney, and Sabo are all a plotline that will probably be tackled post-Wano. I don't think the "smile"(really the nature of devil fruits as a whole)/underworld plotline ends directly with Kaido, there is more here that involves those characters and the revolutionaries, but too much to already happening to tack them on halfassedly in my opinion.
I think they, plus CP-0 and Revo's can all wait until post Wano. We already have like 60+ named characters in an arc that's poised to take another 70-80 chapters at this point to resolve, do we really need additional factions this arc, save for those teased (Whitebeard Pirates or Sword)?