1.) Is it cheating to say Ganondorf, since I hope he'll have a different moveset than CF? If yes, then Snake. Snake and Marth were my faves in Brawl.
2.) Banjo and Kazooie. IIRC Rare technically wasn't a 3rd party developer when the original run of masterpieces they made came out, since Nintendo owned them.
3.) Iunno. Ridley, just for lulz. Don't know any commonly requested ones besides him and Mewtwo.
4.) Rufus Lupus, the dog from Jetforce Gemini. Also Rare, but I believe after they became 3rd party again. Will probably never happen
5.) Hm. Tough one. Maybe...Luffy, of One Piece. He's got a varied moveset, already pre-named for your convenience, many of which translate well into a fighting game like Smash which relies mostly on simple combinations of directional stick + button, which Luffy's moves would flow very naturally from, and he brings some unique properties to the game potentially, perhaps having an in-built damage reduction to bludgeoning attacks (Kirby's Hammer, Cap's attacks, etc.) but a weakness to slashing, making him a bit more of a wild card, being better in certain match-ups and worse in others.