Yeah but could you could also see it as Blackbeard attacking the Marine Ship because well it's a Marine Ship and not because they wanted to save the other ship.
I do still think could maybe be Dragon but the problem with Dragon is that he was all the way back at Kamabakka Kingdom, I don't know how Dragon and his rev could travel all the way from Kamabakka Kingdom to Egghead that fast and even with Dragon's Wind Power I'm still doubtful.
Blackbeard on the other hand is already close to Egghead, him traveling from Winner Island to Egghead shouldn't take that long.
And other than Dragon or Blackbeard, I really don't think it's anyone else.
Plus with Augers warp fruit, he could potentially get them all there in record time of he can warp the ship itself, even if its not that far or often, cutting some distance amd time at least.
But yeah I can see BB showing up to repeat what he did at Marineford and thus try to take Saturn's fruit, York too whilst he's at it, the Seraphim etc.
Or he's gonna try to get Saturn to help him become a part of the WG, get Beehive to accepted as a WG affiliated kingdom or whatever.