No, Buggy/Alvida are chasing after the Strawhats.
Here's all of the people have some kind of reason to go to, or be at Impel Down now or sometime in the future (stretching it a bit):
Ace/Croc/Mr.1/2/3 (All captured)
Whitebeard (He's definitely going to attempt some kind of rescue attempt)
Blackbeard (He's definitely going after Whitebeard after being raised to Shichibukai status)
Shanks (He's the one that brought up Blackbeard's threat level, he might be there)
Garp/Coby/Helmeppo/Kuma (They're currently together at the Marine Base, although we don't know how close that is to Impel Down. Probably not Coby or Helmeppo yet, though.)
And if Impel Down is somewhere nearby Merman Island, then we could add Jimbei and the Strawhats into the mix, as there is no way the plot would stop them from doing otherwise.
Hell, let's throw in Buggy for some good Gol D. Roger and Shanks backstory, Smoker just for the heck of it, and we'll get what looks to be the biggest clusterfuck of awesome in OP.