Chopper fighting him makes the most sense, given the past history, and his close relationships with the minks, especially Carrot whom he asked to refer to him as a big brother.
Pedro also basically killed himself to save Chopper and Brook, and the two of them were cursing their weakness after his death.
The Beast Pirates match-ups for the F6 are pretty much already known, so that leaves Chopper with either dealing with the Numbers, or as part of a tag team against Perospero. I'd prefer the later, or being one of those who take out the remaining Numbers, but also getting the fight with Perospero.
No it doesn't and you could say a similar thing about Brook fighting Perospero as well. You already have Sanji vs one of the Calamities, Jinbe vs Who's Who, Franky vs Sasaki, Usopp and Nami vs Page One and Ulti, and Robin and Brook vs Black Maria.
Chopper isn't going to be the only SH to not fight a member of the Beasts Pirate, he's either going to fight the strongest Number or he's going to tag team against Queen.
Just because Chopper was cursing at his weakness doesn't mean Chopper has to fight Perospero, and remember the main goal of the SHs is to take down the Beasts Pirates. Someone like Perospero is going to be left for Carrot as again she has more of a reason to fight Perospero than Chopper, Oda has always set up Perospero and Carrot to fight and Carrot's defeat sets up another rematch between the two. Now again Chopper and Carrot together fighting Perospero that's a maybe, however in a 1v1 I don't think that's going to happen.
Also in your earlier post you say this is the end of Chopper vs Queen and give your reasons, however your post doesn't completely prove that Chopper isn't fighting Queen. I'm against Chopper fighting Queen in a 1v1, but Chopper tag teaming against Queen with the help of either Sanji or X Drake could still happen. So yeah no matter what excuses you try to make, I don't see Chopper being the only SH to not fight a member of the Beasts Pirate.