Well for our favourite villain it would be either Queen Chrysalis or Nightmare moon (me!)
And for background pony... hmm... that's a hard one... It would have to be Octavia Melody, as she has a really pretty mane and name.
She also produces great music and your princess of the night loves music almost as much as she loves video games.
Thanks klnightgirl for this suggestion 😋
Also, don't hesitate to ask more than one question and it shall be answered!