I believe Moona had to go to a local place to get 3D captured. It was actually Risu that came to mind for a stand-in dancer. They can also touch-up 3D capture if they have it early enough, so there could be a little bit of touch-up work here and there. It's not something to think too much about. Most of that would be about avoiding jank.Was there some hints or rrats about ID girls getting "sick or hurt" during 3rd Fes? First time I heard about it.
Also, that would have included Moona, who is probably just as proud of her dancing ability as Kiara, she bragged about it way back during her debut stream. I remember her performance in 3rd Fes blew everyone's mind, imagine if it was just a stand-in...