1.) Is there any possible way of keeping Meloetta-P without having Relic Song in its moveset? Also, does the Relic Song work in a similar way like Giratina's forms such that Meloetta is in Pirouette (spelling?) already by having the move or does it have to be used first to switch Forme?
It starts always as Aria Forme, and has to use Relic Song in battle to become Pirouette Meloetta. It resets on every switch back to Aria.
2.) With the advent of B2W2, I was trying create Haxorus sets. I've come up with a Choice variant. Would this be a good one?
Aqua Tail - allows Haxorus to strike Skarmory with neutral damage at least without the stat drops.
Outrage / Dragon Claw - STAB
Earthquake - Good coverage with Dragon Claw or Outrage
Superpower - Decent coverage move for Blissey and Ferrothorn.
If I wanted Dragon Dance, what move should I give up?
Either Superpower or Aqua Tail, I'd go with giving up Aqua Tail as Superpower still hits Skarm hard.