^ Other than Maradona, the only costume I recognized was the photographer with the vest and camera. That girl cosplayed as Yoichi Watanabe, a photographer known for his war photos.
The KARA/DARA thing made me curious. The vibe that I got was that Aoi created a knockoff group, know as DARA, but I don't know if they performed musical numbers,
My theory is also based on one of the Muscats saying that she is also a member of DARA, and well as saying Aoi is the leader.