That Dixie Typhoon was more along the lines of what I was thinking, but some of the others I see potential for too. For the spinning one, I was thinking she could throw the opponent, but not have it be an instant K.O. Instead, the opponent has the control stick go round and round, as in you'd have to press left to go right, then it could be up, etc. etc. etc. to signify dizziness. This has the added benefit of the character possibly randomly flying off the edge.
Kiddy Kong would be okay, I presume. But I'd heard a post about how all the characters have to use their own power. The guy said that even Pit's has his own power, and that summoning Palutena (spelling?) would require massive amounts of energy. Heck, even King Dedede's would, I would think, as he'd have to try to get all his servants together, which would take a while. I just can't see how Kiddy Kong would be in that category.
Rambi: I've stated before that he would, in my mind, be better off as an assist trophy, but if you could give me a little description I might change my mind.
Bubble Gum: To be honest, I think I stressed the bubble gum too much. I could see it as a Final Smash where enemies move SUPER SLOW and their attacks are as laggy as Ike and beyond.
The Medusa idea is terribly out-of-character and I would not think it would fit her character at all. I just picture her with these jagged yellow teeth and snakes every time I think of that.
Those are my ideas.
EDIT: Didn't see that last post, but it gave me an idea. In the end of DKC3, the secret ending or something was the Banana Bird. Maybe she could chase characters around the stage and capture them in eggs while mini-Banana birds go inside the shells and peck at the characters? It's game-related, at least.