u/Some-Bath3211

In Diva F, the game coded that if the main singer was Teto, Sakine Meiko, Neru or Haku then Len will be kicked out from the PV and replaced by Miku instead.
In AFT, Len, Rin and Luka were treated as stage prop so only the main singer can be changed, except this time Len won't be kicked if using Fanloid or Teto modules.
In FT/MM/MM+, song that used to treat multiple singers as prop like Continuing Dream, Senbonzakura, Decorator, ... etc were converted into actual singer/guests, allowing players to change their module freely