IMO, it doesn't make sense for Momonosuke, especially if Yamato joins. He does not need to 1:1 parallel his father. The point of the previous chapter was that he doesn't have to live under the shadow of his father, that he's his own man in the Kozuki bloodline.
I can see multiple people joining this arc, namely Carrot and Yamato along with Jinbe (and that's certainly a mega sized if right now), because all 3 have wildly different backgrounds, and 2 of them have been in the story for nearly 200 chapters (Carrot) and 500 chapters (Jinbe) respectively.
The next year or so is gonna be really interesting if we get smaller flashbacks for Jinbe (to explain his dream more/scar possibly), Carrot (for her relationship with Pedro) if she encounters Perospero at all, and Yamato (who definitely is getting a flashback considering Ace and her father).