I still wouldn't take Kojima's words seriously just yet considering if Snake is in the game, saying he's not involved is the only thing he could say. If he said, "Yes, Snake is returning", Sakurai would probably be angry at him for ruining the reveal. If he said "No comment", that is pretty much saying he's in as well since anytime somebody says No Comment on a Yes or No question, it means Yes but they're not allowed to say it.
Plus I find it rather suspicious that Kojima says he doesn't know, when putting Snake in Brawl was his idea in the first place. You're telling me the guy who's suppose to be a big fan of Smash Bros and is friends with the creator of the series, who wanted Snake to be in Melee but asked too late, but then got him put into Brawl from the very beginning, has no idea if the character he begged to get in the first place isn't going to return?
Now I'm not saying Snake might not return, who knows considering he's still a third party and we don't know what could be going on behind the scenes with Nintendo and Konami. But Kojima's excuse about not knowing just strikes me as rather odd considering how Snake got into Brawl, and unless him and Sakurai got into a fight and are no longer friends since then, I have a hard time believing he really doesn't know.