Quoted By:
Team Pirate King!
Ambipom (Rash Nature, Pickup Ability, holding leftovers) - Monkey D. Luffy
Moves: Double Team (Gear Second), Work Up (Haki), Giga Impact (Gear Third), Bounce (Balloon) (Bonus: used to know Low Sweep (whip), Dream Eater (Poor Sanji), Fury Swipes (Gatling), Rest and Frustration) He could also learn Aerial Ace for his brother, if you like.
(Infernape would work too, but I like this more)
Hitmonlee (Naughty, Reckless, holding Destiny Knot) - Sanji
Moves: Hi Jump Kick, Blaze Kick, Close Combat, Rapid Spin
Bisharp (Adamant, Inner Focus Ability, Choice Band) - Roronoa Zoro
Moves: Swords Dance, Night Slash, Metal Burst, Guillotine
(Zoro could also be Scyther, Kabutops, Haxorus for the blade in the mouth area, or of course, Aegislash)
Castform (Sassy, Forecast Ability, holding Amulet Coin) - Nami
Moves: Weather Ball, Thunderbolt, Attract, Thief
Winter Sawsbuck (Naive, Sap Sipper Ability, holding Lum Berry) - Tony Tony Chopper
Moves: Horn Leech, Charm, Mega Horn, Hidden Power (I'd teach him dig or Bulk Up if he was able)
Bouffalant (Lonely, Soundproof Ability, Holding Metronome) - Brook
Moves: Scary Face, Swords Dance, Round, and then Skull Bash (SKULL JOKE) or Uproar, your choice.
(Also acceptable, Shedinja, Cricketune, Chatot, Dusclops)
I couldn't think of one for Nico Robin (Cofferigus?) Or Franky (Klingklang or Golurk?) or Usopp (need seed moves and a hammer move and there's no real sniper pokemon I can think of.)
So fuck it, there it is.