Eh the issue with kuma joining is he doesn’t have a dream that really connects to luffy becoming king of the pirates so far. Seems like he’s like mihawk who just wants to live in peace
Both Kuma and Bonney as canidates have a fatal point that has to do with Kuma living through the arc and gaining his free will again
After all the trouble the two went through they're more than likely not gonna want to seperate again especially since a lot of Kuma's motivations for what he's done throughout his past revolve around Ginny and Bonney. As well as the fact that Bonney's main goal is to help her father
It's gonna be a Rebecca and Kyros situation when it's all said and done