Still no explanation for Toshiro's growth spirt, I guess that is one of those unanswered questions. But grown up Toshiro looked awesome, why he doesn't like that form, I don't know.
So Kenpachi still not out of the fight, and Byakura is planning something, so they are trying to team work, that is something you don't see much in Bleach intentionally team work especially from Kenpachi, I guess you can call it character development.