It's not news to anyone that the Shichibukai don't often follow the World Government's commands. It's just now with the impending war with the Whitebeard pirates that the Government is actually beginning to enforce their side of the contract. Faced with the option of expullsion from the Shichibukai, which members will actually show up? Even Boa Hancock initially rejected the call to arms, and she had perhaps the most justified motive for accepting the position. It's doubtful all of the Shichibukai would risk their lives against Whitebear's forces just for the sake of their titles and perks.
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Boa Hancock is heavilly involved in the current arc, and is seemingly getting involved for Luffy's sake. Whether or not she actually goes the entire way, and remains loyal is still up for debate, though. I personally don't think she'll retain her status.
Kuma has been playing messenger boy, and letting the other Shichibukai what's going down. Near-Certain he'll show.
Moria and Oz were just trampled by the combined force of the Straw Hats. Providing his recovery rate is the same as Zoro's, he should be getting back on his feet right about now, but If Moria heals more slowly than Zoro, he may very well be incapable of fighting yet. I presume the coverup of the Thriller Bark incident is reason enough to believe Moria may be given an excused absence. If not, Moria has more important things to handle: Like rebuilding his army.
Mihawk could really go either way, depending on his mood. The coagulation of powerful enemies and the risk of losing his status make it seem a little more likely.
Blackbeard went out of his way to become a Shichibukai, and played a massive role in triggering the war. Almost certain.
Jimbei- Nothing to speculate on.
Doflamingo seems to be more of the buisness type, and the freedoms granted as a Shichibukai are valuable in that sense. So, he'll come.
