Vegapunk wont join, pehaps he will ride to Elbaf with the SH, to develop more the Library plot.
But i would prefer If Robin was alone to get the info there, we dont need him sharing the panel time with her, especially as he already know the info, while Robin and us the readers would be learning the infos.
Think he will work as a way for Oda to give some power-ups to the SH. Ussop, Nami, Sanji, Chopper and especially Franky can get power-ups from him.
For the satelites, they could all be destroyerd by Kizaru, to give at least a little bit of the fealing of danger in the Arc.