Very interesting, I'm not entirely sure where Oda's at here. CP-0 do not seem like direct antagonists (imo, Luffy would destroy Lucci easily anyway), so unless Lucci is somehow good or there are more CP-0 members, I'm not sure what the goal is lol.
Serephim are clearly antagonistic, even if they are being used by Vegapunk currently. Something has to happen where their roles are switched and used against the crew it's just a matter of how and when. Not sure either what Sentoumaru's role will be. It's weird if he directly follows Vegapunks orders, considering Kizaru, but we'll see.