Hey /vp/, scrublord here

So, I'm pretty new to pokemon battles, tactics and whatnot. However, this does not stop me from trying to build my own team to sweep trough the Super Single Battles in the Battle Maison. It has been fairly successful so far, I'm at 15 wins, the farthest I've ever been. I'd love to hear you guys oppinions and recommendations on the current party, which is as follows:

Greninja with Life Orb
1.Surg
2.Dark Pulse
3.U-Turn
4.Ice Beam
I trained SpA and Spe to the max.

Metagross with Assault Vest
1.Meteor Mash
2.Earthquake
3.Hammer Arm
4.Zen Headbutt
Trained Attack to the max and Speed/HP about the same I think

Dragonite with Leftovers
1.Dragon Dance
2.Fire Punch
3.Dragon Claw
4.Roost
Used it on my team to beat the story, so all it's EVs are kinda fucked up. Has fairly high attack, tho.

I read a lot on Smogon about how to EV train, what to EV train, what natures to use and what abilities would work best. The pokemon choice dependet on how much I like a pokemon or not.

I'm open for any kind of help, thanks in advance!