Okay I like this team just needs a few changes. Changes will be in bold.
Metagross-Mega @ Metagrossite
Ability: Tough Claws
Level: 50
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Ice Punch
- Zen Headbutt
- Protect
- Iron Head
Not much to change here, just get Jolly to out speed those key threats.
Hydreigon @ Choice Specs
Ability: Levitate
Level: 50
EVs: 4 HP / 252 SpA / 252 Spe
Modest Nature
- Draco Meteor
- Dark Pulse
- Flamethrower
- Earth Power
Also really good, dont waste 4 EVs in attack, put them in HP. Also since you have speed control, take advantage of that and dish out some heavy damage, with Modest Specs Hydreigon.
Suicune @ Sitrus Berry
Ability: Pressure
Level: 50
EVs: 252 HP/ 156 Def/ 76 SpA/ 4 SpD/ 20 Spe
Bold Nature
- Ice Beam
- Scald
- Snarl
- Tailwind
This is really good. Just use this EV spread to optimize a nice balance between bulk and power.
Gengar @ Focus Sash
Ability: Levitate
Level: 50
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Icy Wind
- Taunt
- Shadow Ball
- Will-O-Wisp
Like Grime Time said,you need shadow ball. This team has a minor Ghost weakness, so you would need shadow ball to go 1v1 with Pokemon like Aegislash and opposing Gengar/Mega-Gengar.
Terrakion @ Lum Berry
Ability: Justified
Level: 50
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Rock Slide
- Double Kick
- Close Combat
- Protect
Again you need Jolly to out speed targets. Double Kick to break subs and sashs. Everything else looks good.
Escavalier @ Life orb
Ability: Shell Armor
Level: 50
EVs: 252 HP / 252 Atk / 4 Def
IVs: 0 Speed
Brave Nature
- Protect
- Megahorn
- Drill Run
- Iron Head
You are weak to trick room. Well say hello to your hard core trick room counter. Make sure he is Brave, and has 0 EVs and 0 IVs in speed. He will Under speed all Pokemon in the Metagame. Drill Run is there since earthquake was removed. Drill Run can kill Mega-Camerupt and nail Aegislash while he is in Blade form. Iron Head and Megahorn are strong STABs that hurt coming off that 135 base attack. With Megahorn he can destroy the most prominent trick room setters, and then thrive in it for the next 5 turns. Life Orb was used to maximize damage output but still allow moves to be switched between; if desired though other items (Leftovers, Rocky Helmet, etc...) could also work.
Overall very good team. Only one major change was needed, and that was to a Pokemon with the same typing. I hope you like this answer. Have a great rest of your summer!
-Unstoppable