1. Aang: AS puts him on a whole 'nother level, even his kyuubi powers wouldn't get him close enough to Aang who can launch attacks from a long distance away with the whole damn arena or whatever as his weapon. Unless Naruto's new jutsu we haven't seen yet can mess stuff up from far away, he can't touch him.
2. Sasuke: My working theory is that the Sharingan wouldn't be able to follow the bending, since chi is to Avatar what chakra is to Naruto(even though Avatar uses the term chakra too it's more in the traditional sense), still Zuko gets overwhelmed eventually because he just doesn't have the same mobility or stamina as Sasuke.
3. Since the only Fire Lord we've seen was during the comet, we'd have to say that's the version that'd fight. I think he'd give Itachi a quick run, but unless Ozai knows about genjutsu before hand, that'll get him and the fight is over in a few minutes.
4. Sakura's only edge is her strength, so she'd pummel any boulders flung at her, but I don't see her compensating for Toph going underground and attacking from below, or kicking up a bunch of dust and using zero visibility to her advantage.
5. Katara freezes Hinata's butt cold. No need for further break down as I don't know jack about her.
6. Asuma puts up a decent fight but a blast of lightining to his face ends the fight.