Gunko vs Zoro and Brook: Lost man vs Redirection. Zoro was introduced tied up, and called a Demon/Monster. Gunko was introduced beating up a man in the same circumstances (Loki). God we need a Zoro/Brook team up fight. Since Brook can cut Souls, I'm wondering if he can damage the God's Knights (IMO they are using their Shadows to heal themselves, like a reverse Moria Zombie situation).
Sommers vs Sanji and Robin: Love brawl. Robin/Nami get hurt, Sanji pops off. I'd love to be wrong, and for Sanji to get CoC. Sanji threated Shaka for making Robin cry, and asked S-Shark if he knew about the power of love. Like S-Shark, the children are currently following orders, and "touching" them hurts them. Sanji asking Robin for help in Onigashima foreshadows this fight.
Gillingham vs Luffy and Jinbei: Gillingham is so goofy, and Zoro and Sanji's imaginations are boring. Luffy's imagination is WILD. Sounds like what Oda would draw. Also the fact that Gillingham looks like Momo isn't lost on me. Sommers and Gunko don't seem very... talkative compared to Gillingham. Gillingham seems like a cool dude, too; I'd imagine he and Jinbei know each other, since Jinbei was the Shichibukai who tried the hardest to work with the WG to make peace. Warcury praised Jinbei highly before Marineford; the (socially intelligent) Celestial Dragons clearly have respect for Jinbei as a peacemaker/representative of the Fish-Men and Merfolk.
Edit: After consideration, I believe Chopper will heal Saul, Usopp will fight Gillingham (fears), Franky will fight Sommers (Family), and Nami will fight Gunko (kidnapped Colun, and Oda typically has Nami fight women).