Moria is going to be the first big name to join through perona and her ties to mihawk. Him having no where else to be anyway. Once he learns they’re going to go for the one piece together it gives him even more incentive to join them. Plus it’ll give him a chance to get his revenge on bb or even luffy
We already know persona is joining anyway
If crocodile does plan on going to impel down he’s definitely gonna try to make Doflamingo and Bentham join. Bentham bringing along his level 5.5 friends. Doflamingo while not being the type of person to bow his head to anyone might not have much of a choice. With it being between joining them and being free or staying locked up and potentially dying. It would also give him a chance to get back at the world government joining a group like cross guild
It’s also pretty funny if emo goth mihawk is the reason emo goth perona and Moria join while potentially transgender crocodile is the reason the flamboyant Bentham and Doflamingo join
As for the 2 on the bottom aka Shanks and Dragon it would be dope as hell to find out they are in some way connected. Dragon should definitely be at least a bit knowledgeable on shanks do to being a good amount older, his respect for Roger, and the time shanks spent with luffy
We know dragon is after the celestial dragons and Shanks the Blackbeard Pirates so it’s even more likely they end up crossing paths once Blackbeard does with imu