Gardevoir can learn Aura sphere!?

Nope.

Hm...Hyper Beam is good for Mega Gardevoir because of Pixelate. I would say have Psychic as well. Maybe Shadow Ball. It really depends on what your team is. I like to give it one STAB move for each type.

Never mind Aura sphere and go for: Shadow ball, dazzling gleam, or moonblast.

She can learn Focus Blast though.

Nah. Even with Pixelate, the recharge turn would still spell out doom for Gardevoir, especially since Moonblast, despite not being as powerful, would still probably handle everything a Pixelated Hyper Beam would.

Shadow Ball is good though.

And drop Double Team. I know you really love it, but Gardevoir's speed isn't reliable enough to pull it off.

time to find heart scales.

Depating about switching Fletcher for Noibat as my flying type.

I got one through wonder trade and it doesn't look like you can catch one till late game.

I don't even know where you can find them.

Yeah, that's the drawback to Hyper Beam. If you had bred it to know this. Synchronoise is a really good move, since it can go through a Substitute.