Been playing through this game and I'm on chapter 13 right now. I have counted 3 kisses so far in the game, each one doing damage to their opponent. Ingrid from Street Fighter has one, Morrigan from Darkstalkers has one and a skill move that cures aliments but I don't think it has any visuals, and Saya from Namco X Capcom has one.
So far they are all blown kiss attacks and no direct kiss attacks but there are plenty of other characters in the game that have potential to have one. I will let you guys know if I find out any more as I playthrough the game.
BTW, this game has A LOT of fan service in it! Tons of heart animations and booty bump attacks that are right up my alley!