Lets get to work.
Firstly- your EV's don't really suite the role of your Pokemon. So I would recommend:
Metagross: 252 Atk. 252 Spe. 4 HP
Salamence: 252 Atk. 252 Spe. 4 HP
Gengar: 252 Spe. 252 SpA. 4 HP
Infernape: 252 Atk. 252 Spe. 4 HP
Spiritomb: 252 SpA. 252 Spe. 4 Def
Froslass: 252 HP. 252 Def 4 SpD
Thing is you only have one Hazard Setter.
A Sweeper sweeps teams with attacks so it needs speed and attack.
Infernape is looking good although one good thing for this would be to run a SubPunnch set.
252 Atk. 252 Spe. 252 HP
- Focus Punch
- Fire Punch
- Thunder Punch
This set really suits your team well.
Since this is OU. I would say replace Spiritomb with a Prankster Sableye.
252 HP. 252 Def. 4 SpD
- Night Shade
This set gives you fullproof against Taunt and works well otherwise.
Your Salamence is good. Just use the EV spread I gave above. And give it a muscle band.
For Metagross. I would say run a HC sett.
252 Spe. 252 Atk. 4 HP
- Meteor Mash
- Zen Headbutt
- Hone Claws
Btw I would say replace Froslass with a Jallicent.
252 HP. 252 Def 4 SpD
- Shadow Ball
- Ice Beam
I love this set.
So this is all I would suggest!