WRT Jimbei, Luffy specifically asked him and he was like, yeah maybe but I have some stuff to deal with first
and his time working for Big Mom helped the SHP in WCI obviously.
Vs Yamato, who wasnt really wanted by Luffy as much, and has no real plot reason to stay in Wano, at least based on what we know so far
Seems like Yamato will just be an ally who helps out Momo