Chapters 1014-1016 are super interesting in terms of Yamato and possibility of a new Nakama.
Let’s first talk about Chapter 1014 because I think this is a hint at what Oda is trying to do with Yamato’s Oden situation. A lot of people are interested in Joy Boy revelation because it hints that someone can become a Joy Boy, and not just born as the next Joy Boy. In this sense, Joy Boy is a title, and not just a name of someone from the past.
But what interest me is that while at present day it is seems to be a title someone obtained, Joy Boy is most likely still a name of someone from the past. And this have an interesting implication for Yamato and his “Oden”, because it suggest to me that Oda will develop Yamato’s story in similar way, that Oden is no longer a name of a person, but a title that someone obtained.
Wano has a lot of parallels with previous stories of One Piece and Oden is no exception. Oden has a lot of parallel with Joy Boy (lost a war with the current ruling government in the past, the current government is actively vilifying him and his factions, etc.) and the way Yamato wears Oden’s clothing seems to parallel the fact that Luffy wears the strawhat like Joy Boy.
So instead of “I am Oden, not Yamato” or “I am Yamato, not Oden”, it is very possible that the endgame for Yamato is “I am Yamato the Oden”.
Chapter 1015-1016 really gives more fuel to Yamato as the next Straw Hat, but I think the little detail that is missed by people is that in chapter 1015 Luffy is asking everyone to fight until the last because he is going to defeat Kaido.
So when Yamato says he is holding back Kaido until Luffy arrives is him obeying his captain’s order once again.
The Roof Piece between Yamato and Kaido is also deliberate by Oda to symbolize where Yamato is standing in term of strenght (on Monster Trio level and not in Brook-Franky-Robin level).
I believe Yamato and Carrot will both join, and instead of Monster Trio (Luffy, Zoro, Sanji), Weak Trio (Nami, Usopp, Chopper), and Adult Trio (Robin, Franky, Brook), we are going to get Monster Quartet (+Yamato), Weak Quartet (+Carrot), and Adult Quartet (+Jinbe).