Ok so here is the alternate roles.

Princess celestia= Queen cryslys

Princess Luna= princess fluttershy (better then rarity right?)

Elements:

Magic= discord

Kindness= nightmare moon

Honesty=Sombra

Loyalty=tirek

Laughter: Derpy (just cause she's awesome)

Generosity= trixie

Bad Guys

Discord= twilight

Nightmare moon = fluttershy

Sombra= rarity

Tirek= rainbow dash

Derpy= pinkie pie (CAN'T HELP IT THEY SO FLIPPIN AWESOME)

Trixie= Apple Jack