@i:
Hodi v. Jinbei
VDD v. Luffy
Caribou v. Sanji
Hyozo v. Zoro (obviously)
I would agree with Sanji's if it wasn't for Ikaros Much and his fire weakness, not to mention the squid looks like the second strongest of Hody's gang after Hyozo.
Following the powerscale and the examples of Alabasta and Enneas Lobby, Zoro will fight the second strongest after the boss, while Sanji will fight the third strongest, and of course Luffy will fight the boss himself.
In the previous prescedents:
Alabasta arc
Luffy vs Crocodile (boss)
Zoro vs Daz Bones (number in the rank says all)
Sanji vs Bon Kurei (idem)
Enneas Lobby arc
Luffy vs Rob Lucci (boss with 4000 doriki)
Zoro vs Kaku (2200 doriki)
Sanji vs Jabra (2180 doriki)
Therefore…
Gyojin Island arc
Luffy vs Hody Jones (boss, powered up after taking so many E.S.)
Zoro vs Hyozo (strongest swordsman fishman of the island)
Sanji vs Ikaros Much (roasted squid is a delicatessen)
This is my bet for the "Monster Trio" fights.
Caribou is after Shirahoshi, so Luffy shall kick his ass. Not to mention he's logia, and I doubt there's someone in the crew other than Luffy that learned CoA.