@Joy_Boy's_Will:
Caesar is important for Kaido and big mom, so i assume that's why he's still around. Where will he go after is a good question, I have no idea.
Yeah, sure, but I don't see them handing him out to either of them. Law only bargained with Joker, so he would resign from the Shichibukai and use the opportunity to distract him, while the others would destroy the factory. Everything was planned to strip Doflamingo from his power.
Law has no interest in taking on Kaido or Big Mom, he just said it to get Luffy on his side (atleast that's how I interpret it), in reality all he wanted was revenge for Corazon.
And Luffy has no interest whatsoever in bargaining with the Yonkou. All he wants is to punch them in their faces and scream "I will be Pirate King"
I suppose Smoker could show up and they will send Caesar to Impel Down sometime down the road. Or, heck, redemption arc and new nakama. Or what was said before: Tie him on a tree and leave him there (but that would leave things open for his return). I really really don't know how big Oda's plans are with him.