The only thing I consider sure is that the fight won't happen in the tower (can't handle this fight) so my guess is Onigashima entrance, basically where Linlin clashed with Marco. I think that Kidd (and Law?) will be defeated at some point, but that's when he'll use Onigashima sword. He'll learn adv. CoC in the process or right after that.
In a nutshell: imo the battle will happen at Onigashima entrance, Kidd will have 2 PU (sword, adv. CoC) and will defeat/be the one who makes Linlin retreat (if she doesn't fall in Wano, which I doubt to be the case).
What you think?