Character list!
Miku: SpicyMelonCake
Rin: @NovaForTheWorld
Len: Anime_Obsession_02
Luka: SilverStarSparks
Meiko:
Kaito:
Gumi: @NovaForTheWorld
Gakupo:
Yuuma: Anime_Obsession_02
Kuroe Kagami: @Yuki-Kagami
Nika Utatane: Utatane_Nika
Hanako Koizumi: @FragileCrystal

(I only added the other vocaloid 8 as an idea for who's open!  Will update as soon as more join!)