I think that the 10th TC will be Sanji’s BBP opponent since none of the others have convincing enough setup to be Sanji’s opponent.
Blackbeard - Obviously not Sanji’s fight
Shiryu - Only setup he has is having invisibility, but he’s obviously Zoro’s opponent.
Lafitte - He is definitely one of the more prominent BBPs, which you could argue is because he will fight the #3 of the SHs, but I think Lafitte is given more prominence because he will fight Nami. Nami is one of the 3 “cores” of OP (along with Luffy and Zoro) according to Oda, so it makes sense that her opponent would get more screen time. Lafitte being a navigator and former cop seems like good setup for him to fight the navigator and cat burglar, Nami.
Van Augur - Obviously Usopp’s opponent
Doc Q - Obviously Chopper’s opponent
Catarina Devon - Basically no setup. The only thing that could be gained from Sanji fighting her would be him finally hitting a woman, but Oda obviously wants Sanji to remain sexist
Sanjuan Wolf - No setup
Vasco Shot - No setup
Avalo Pizarro - He has setup due to being North Blue royalty, but in my opinion, this would be very shallow setup. Just look at how much Shiryu seems to contrast with Zoro. Shiryu is very obviously a dishonorable swordsman who’s willing to use underhanded tactics like sneaking up on someone from behind, while Zoro is an honorable swordsman who would never use cheap tricks. Pizarro simply just being evil North Blue royalty isn’t nearly as much of a contrast with Sanji’s character as Shiryu is with Zoro’s character. Not to mention that Shiryu always stood out from the rest of the Level 6 prisoners from the get-go, while Pizarro doesn’t stand out from the rest at all, and you’d think that Oda would try to portray Sanji’s opponent as a cut above the mid trio’s opponents (since the mid trio will most likely fight Level 6 recruits).
The fact that the 10th TC was the only recruit during the TS and that he still hasn’t been revealed yet suggests that he will be a heavy hitter in the BBPs. After all, why keep him hidden for so long if he’s just gonna fight someone like Brook?
Blackbeard - Obviously not Sanji’s fight
Shiryu - Only setup he has is having invisibility, but he’s obviously Zoro’s opponent.
Lafitte - He is definitely one of the more prominent BBPs, which you could argue is because he will fight the #3 of the SHs, but I think Lafitte is given more prominence because he will fight Nami. Nami is one of the 3 “cores” of OP (along with Luffy and Zoro) according to Oda, so it makes sense that her opponent would get more screen time. Lafitte being a navigator and former cop seems like good setup for him to fight the navigator and cat burglar, Nami.
Van Augur - Obviously Usopp’s opponent
Doc Q - Obviously Chopper’s opponent
Catarina Devon - Basically no setup. The only thing that could be gained from Sanji fighting her would be him finally hitting a woman, but Oda obviously wants Sanji to remain sexist
Sanjuan Wolf - No setup
Vasco Shot - No setup
Avalo Pizarro - He has setup due to being North Blue royalty, but in my opinion, this would be very shallow setup. Just look at how much Shiryu seems to contrast with Zoro. Shiryu is very obviously a dishonorable swordsman who’s willing to use underhanded tactics like sneaking up on someone from behind, while Zoro is an honorable swordsman who would never use cheap tricks. Pizarro simply just being evil North Blue royalty isn’t nearly as much of a contrast with Sanji’s character as Shiryu is with Zoro’s character. Not to mention that Shiryu always stood out from the rest of the Level 6 prisoners from the get-go, while Pizarro doesn’t stand out from the rest at all, and you’d think that Oda would try to portray Sanji’s opponent as a cut above the mid trio’s opponents (since the mid trio will most likely fight Level 6 recruits).
The fact that the 10th TC was the only recruit during the TS and that he still hasn’t been revealed yet suggests that he will be a heavy hitter in the BBPs. After all, why keep him hidden for so long if he’s just gonna fight someone like Brook?