It actually makes sense that Jinbe wouldn't have met Boa in person before, even if he knows her by reputation. You keep mentioning them being on the "same squad" but they mentioned at the start of this whole War-plot, that getting all the warlords in one place like this is nigh-unprecedented.
All the way back the first time we saw the "round table" to figure out how to replace Crocodile being abolished, everyone was astounded that even 3 of them bothered to show up, and doubly so because one of them was Mihawk who has apparently never been there before in his life.
The World Government doesn't tend to enforce the rule that the Shichibuki need to abide by the summons unless there's something massively important happening like; say, imminent war with the strongest man in the world.