Luffy vs Blackbeard, duh
Doc Q vs Chopper, doctor show off, and given Choppers past experiences with doctors, thatis what makes him most worked up.
Zoro vs Shiryuu, swordsman duel, with Shiryuus new df giving him some even more ominous aura matching Zoro.
Catarina Devon vs Nami, Devon hunts and decapitate beautiful women, Nami is a beautiful woman, Devon should also have some more spells, illusions and tricks along with her DF making an interesting match up for our monkey king weather controlling sorceress.
Brook vs Lafitte, demon vs angel, both thin and carrying canes.
Jinbei vs Vasco Shot, in my head canon Vasco shot is a drunken kung fu master, seawater vs alcohol, lol.
Tama vs Sanjuan Wolf, typical david and goliath match up, with some jack and the beanstalk theme, that will hopefully end up like a giant kaiju battle between tamas potential pet and sanjuan wolf.