In the spirit of actually moving on, Luffy showed a lot of interest in ninjas. It didn't quite get to the level of his interest in having a musician, but enough that I did think Oda was going to have a ninja join. Tama is the obvious choice, with her desire to leave, her connection to Ace, her bond with Luffy and then the rest of the Straw Hats. She's shown she's pretty shrewd, coming up with the plan to use Big Mom to break into Udon as well being a major contributor to the raid with her Devil Fruit. The only thing really holding her back is her age, but we now have Shinobu who could take care of that problem. Luffy taming beasts (Kung-Fu Dugongs, Kraken, the animals at Rusukaina) also renders her Devil Fruit pretty redundant. Of course, I think it's far more likely after the raid that she starts being tutored in being a kunoichi by Raizo and Shinobu and remains in Wano both to fulfill her wish to see Momo become Shogun and Luffy's promise to make Wano a place where she'll never go hungry. I just think Shinobu being able to age people up gave Tama a slight bump in her chances.
That being said, I would have actually liked Raizo or Shinobu if a ninja was going to join since either of their Devil Fruits combined with ninja skills could actually have led to some interesting fights. Personally, Yamato's Devil Fruit killed quite a bit of my hype for her. A mythical Zoan could have been cool, especially since so little is known about the Makami so its unique ability could have been anything. I don't get why Oda decided on just slapping on ice powers. That just feels underwhelming. If I had to guess, it's supposed to contrast Kaido's fire (and if she joins and fights Catarina Devon, her potential foxfire since she's a Kitsune). I would have rather had a Paramecia since that at least means some random power that can be used creatively. The most creative thing Yamato has shown so far is ice armor.
I don't think anyone is joining after Wano, not even if we go to Elbaf since I think Hajrudin and his group basically "covers" an Elbaf recruit but we'll probably get a few people sailing with the crew afterward. Yamato either as a crew member or just the new Law/Momo/Kinemon who gets involved in the next big plot going into the final war, Marco to get him back to his village while also giving Luffy and crew a chance to go to Ace's grave and deal with the Weevil subplot, and Caribou since Luffy said he'd take him and to deal with whoever Caribou wants to pass along the Poseidon info to. Law I could see leaving, but he still needs to find out what the Will of D means and hasn't shown much interest in being Pirate King. It's a toss-up at this point whether or not he sticks with the Straw Hats. I could also see him taking up hunting Poneglyphs for Robin in exchange for info on the Will of D when the crew learns it at Laugh Tale.
