For added context, one thing that appeals to me about One Piece is how alive the world that Oda has crafted and blessed us with is. That despite the focus being in one place there's likely to be another thing elsewhere. One thing that we do know is that Wano being "closed" has abundantly...
This theory doesn't have the legs too stand on its own but its an interesting thought.
Jinbe mentions that Who's Who broke out of prison.
The rest I'm going to say is speculation; Who's Who broke out of Impel Down 2 years ago during Blackbeards battle royal to the death. Who's Who is a spy...
So the Blackbeard Pirates are:
Marshall D. Teach
San Juan Wolf
Doc Q and Stronger
10th Titanic Captain
I presume that the Strawhat Pirates Post Wano would be: