There's no need for Noivern to use Choice Scarf because it's already very fast. Dark Pulse also doesn't give Noivern any noteworthy coverage; Draco Meteor already hits Dark and Ghost Pokemon hard enough, while Flamethrower takes care of Aegislash:
-Draco Meteor
-Flamethrower
-Focus Blast
-Switcheroo/U-turn/Hurricane
Nature: Timid/Naive
EVs: 252 SAtk/4 SDef/252 Spe
Item: Choice Specs
Ability: Frisk/Infiltrator
or
-Draco Meteor
-Flamethrower
-Focus Blast
-U-turn/Roost/Dragon Pulse
Nature: Naive/Timid
EVs: 4 Atk/252 SAtk/252 Spe
Item: Life Orb
Ability: Frisk/Infiltrator
Mega Ampharos is way too slow to use max Speed. Its bulk should be the main focus. Its EV spread should be 236 HP/252 SAtk/20 Spe; the 20 Speed EVs let it outspeed Hippowdon.
Thanks for the input it really helps.
You're actually more weak to Fairy than Electric. Noivern is neutral to Electric because Dragon resists Electric. You could put a Steel type in Mega-Ampharos's place. Steel/Water/Dragon makes a decent defensive core.
And Singles in the Battle Spot (in unrated, at least) does 3v3 matches. Or if you meant 3 Pokemon out all at once, there's Triples.
Would Mega-Mawille/Mega-Scizor be a good replacement ? I was thinkin it would also help in keeping people from setting up sp def walls on me. Or was you thinking more of a bulkier Steel type ?