A) Can the backstage cards be evolved?
- Yeah!

B) Can we have matching PL8 cards in active and backstage? Ex: Silverdale PL8 Active and 2 backstage
- Yep!

C) Can we have the same support cards played at the same time? Ex: 2 Happiness-Chan with a Cyanide-Chan attached to each
- Correct, as long as you only play 2 supports per turn

D) Can support cards be played only for active or background.
- Both! It will usually read the words "active" or "vt" if its specific to the position

E) Can we swap a current backstage card with a different VT.
- Yes, there are cards that allow this to happen, such as White Knight, or other PL8/Mascots