So here's my guess how they work:
- Callie and Marie both share five songs. When selected, the venue changes to the concert from Splatfest, and both Callie and Marie sing and dance to the songs, using dance moves from the real-life Kaishen concerts. You can watch and worship your pop idols anytime!
- However, each sister also has an exclusive solo performance that only they can perform. During it, the other sister sits and listens with charming new idle animations.
Is this correct? Seems like a perfect fit for their character concept of entertainers.
I also dig the special textures on the hair and accessories, and glittery plastic they're using for the dresses.