Well, if this turns to be Punk Hazard 2.0, I expect some of them or at least 1-2 to appear here:
1. The old man with helmet, beard and cigar (IMO he is Vegapunk, the original one).
2. The dude next to Rob Lucci (he seems to be robotic or enhanced... Like Franky).
3. The dude with the afro and cigar (he was the most interested guy watching the broadcast of Shinokuni and was even pissed when the experiment was messed up, like if he is some kind of scientist or something, but anyways, he has knowledge about experiments/science somehow).
4. Cowboy hat and headphones duo, they are clearly thugs, but IMO they doesn't know Luffy from the childhood like cover stories. Well, they seems to be at some short of factory/modern building when they show up, and we are probably at the most advanced island from OP verse... So there is chance that they're hired by the World Government, Vegapunk himself or aomething related.
5. Pointy ears guy, he could be also Vegapunk, because Oda likes to play these games.
So, guys, which ones/what are your guess?