lol at the people who think Kuzan is fighting a Straw Hat, or at the people who think Yamato is fighting a Blackbeard Pirate. Kuzan is not going to end up as on opponent who just loses at the end of the arc, he's clearly more important than that. Yamato also isn't joining the crew.
It's pretty clear that the 10 Straw Hats introduced pre time skip will fight the 10 Blackbeard Pirates also introduced pre time skip.
Luffy vs Blackbeard.
Zoro vs Shiryu.
Usopp vs Auger.
Chopper vs Doc Q.
Nami vs Devon.
Don't know about the others, but these 5 feel guaranteed to me. Lots of people bring up Nami vs Lafitte as a possible matchup, but Nami always has fought women. Nami's beauty is also strongly linked to her character, and Devon kills beautiful women for fun. Both also have illusion based attacks.