I agree that Kanou and Kitamura did not start dating. Kitamura respected her decision to move on for both their sakes, so he gave up. I think it was stupid of him to do so. He should have just gone with her and made a new start. What the hell is he even leaving behind in Japan? A bunch of weird friends? A father that beats on him (though he might have deserved it a bit)? On the other hand, Kanou is hot and cold at the same time. What else can you ask for?
On the Ami and Takasu bit, I personally think that Takasu is more of an M, so he needs someone like Taiga or Ami as a match to make him feel satisfied. I just prefer the intelligent painful remarks over actual physical pain from violence. Taiga is just far too brutish and clumsy for my tastes.