Naruto/Luffy - Naruto would have to go Kyuubi, but even then I'm not sure. Luffy's strength is insane and he's not phased by people moving at high speeds.
And kyuubi's strenth is insane with just the one tailed form.
Rasengan would ko or kill Luffy in that state. And Luffy's defense isn't that great. He cuts just as easily as a regular human.
Zoro/Sasuke - If Saskue doesn't have three swords handy at the time, copying Zoro's sword fighting movements isn't going to do anything. Chidori might work if he can get it to hit.
This is a tough one. Because even of Chodori works, I've seen Zolo fight with a hole in his guts and bleede beyond the point of death due to blood loss. Sasuke might be able to win if he uses the curse seal though. Not to mention he doesn't need to copy Zolo's style. The sharigan will just help him to memorize the patterns, making Zolo's moves ineffective.
Nami/Sakura - If Sakura can actually put her strength to good use, she might be able to cave in Nami's skull.
Yeah, but only Sakura after the time jump.
Usopp/Shikimaru - Shikimaru would take it no problem.
Agreed.
Sanji/Rock Lee - Lee takes off the weights and have a definite speed advantage. But if Sanji connects just one kick, it's all over.
I doubt that. Lee was crushed by sand, had his muscles torn, was at the brink of physical exaustion and still could fight. One of Sanjis kicks will not instantly ko him.
Chopper/Shino - If Chopper stays away from him long enough to pop a Rumble Ball and use Brain Point he'll find Shino's weakness and take him down.
Robin/Neji - Neji might win if he get's close, but Robin won't let him. She'll break his neck and/or back before he knows what is going on.
In fact...
Announcer: READY!? FIIIIIIIGHT!!!
::Robin kills them all::
Announcer: ...and the winners are the Straw Hat Pirates...