Can Futtershy scream musically? Probably only when there's no one else to hear. Princess Luna is good at that, though, and it takes more than one pony to be a band. She might need to face away form the crowd like Eddie Van Halen until she got into it on guitar, too. My question is who does drums, bass, and synth?
Applejack is the bass player, of course.
There is no synth. Get your filthy nu-metal heresy out of here!
The rest of the 6 are backup guitarists to Fluttershy's lead.
And the lead singer is, of course, Derpy Hooves.