Probably a part of CP0 but Oda not showing them to keep us guessing as usual.
Could also have been reinstated as CP9 agents with Jabra as team leader, Kalifa's father as the overseer, and new recruits filling the open spots.
I hope Lucci and the gang have an ulterior motive though. Being dogs that do whatever daddy government tells them is so boring and sours their return. It was fine in Enies Lobby, and it served a purpose, but I don't want a rerun of that.