Now first of all not sure how many people have thought about this but what if Caesar Clown joins the crew on some crazy plot twists? As the Scientist of the group yes we have Chopper but he could help chopper and Franky brings us close to Vegapunk.
Yes I know he evil... but is he because he has great interactions with the crew comedy wise and doesn't seem to have a major fear of him as threat at all. Once if you recall Robin was evil an a main bad guy but was forced to do evil things By Mingo (as Luffy would say) and Big Mama now and Kaido all these major powers want to use him and his abilities and his knowledge.
How Crocodile wanted to use Robin for what she knew, if Caesar joins the crew he could enhance the ship with Franky help Usopp, Chopper, Nami increase their attacks also Franky to. It’s clear he wouldn’t replace Zoro or Sanji or Luffy as the main 3 power house of the crew but he does add to what they can do. I know Jinbe is the highly favored to join but what gets me is his interaction with the crew. Not sure what his comedy relfie would be. Caesar could interact with each member alone or in a group with silly faces and antics and still be a value team mate in battle. Like a Brook type.
This is all just a thought I had of course getting into the Yonko series and all this powerful new enemies the crew got to go deeper as far as power and to have a full crew by the end of the story. But I’m end this with a question what if Jewelry Bonney is related to Big Mama possibly even WhiteBeard given the hate she has for BlackBeard, I would like to see how she will fit into this maybe adding another girl to the crew it so many possibilities.