I changed out the names cause, while Scarlet Bell is a cosplayer, the one in the cosplay is Lon. On Bell's account, he was dressed as Futo and seems to be the one taking the pictures.
It looks like they just decided to do this, at random. Great choice, I say ;) - Edit: I just saw some more video. It was for a party. Damn, adding "Attend a Touhou party" to my 'Do b4 you die'-list, lol.