Do we have informations on how long BB was a pirate captain? I mean it doesn't seem as if it was a long time. I had an idea on why Van auger, burgess, doc q, lafitte decided to join BB. I mean wouldn't they be pissed off if BB says to them:
guys we are a crew unless we catch a "big fish" and i become a shishi then the crew will be disbanded. Was it all BBs plan to become a shishi and attack Whitebeard with the marines power (the situation we have now fits even if BB didn't planed to catch Ace)? And if he has done it he would have returned being a normal pirate (non shishi) with his crew?
So they are all accepting the current situation cause they know that their captain will be with the government until his plan is achieved and come back to them.
Not this Shichibukai have to get rid of their crew argument again. Something like that was never stated. Jinbei's crew disbanded. But giving the fact that he's totally different from Arlong it's more likely that this is because Arlong wouldn't want to serve under a guy who works for the WG considering that entire Fisher Tiger deal. For any other Shichibukai it was never said that the same happened. In fact, it wasn't even said that all the Shichibukai were captains to begin with.
And we even have the proof for what I say with Boa Hancock who's still leader of the Kuja Pirates even if she's a Shichibukai. It's not like she did that in secret either.
That's that. About Auger's statement. He said that fate is parting path's once again. Which means that something like that happened before. And in order to part ways you have to join beforehand. So if parted twice then you have to joined twice beforehand. And I seriously doubt that the crew joined together, parted ways, joined together again and now at Banaro Island is to part once again. It would be weird if it meant this. The most plausible thing that it is the Strawhat pirates who've they meant. After all Augers innitial fate statement at Jaya was exactly about them.