EVs would totally be helpful here, dude.
Espeon's EV spread should be 252 HP/4 SAtk/252 Spe.
Breloom's EV spread should be 236 HP/252 Def/20 Spe.
Gengar's EV spread should be 4 HP/252 SAtk/252 Spe. Black Sludge is worth considering, as it annoys Trick users (but also gives them something else that's dangerous to Trick back). While Sludge Bomb seems tempting as Gengar's strongest move, its coverage is very bad. It should use Focus Blast alongside Shadow Ball, as both moves are unresisted together and Gengar is currently walled by Steels. Sure, Focus Blast has the nasty tendency to miss, but Gengar really needs that move. for the reasons I said.
Why is Protect on Cloyster? The last slot should go to Rock Blast to let Cloyster hit the Water Pokémon that resist Razor Shell and Icicle Spear. Only use Naive when you're using Hydro Pump; otherwise use Jolly. EV spread should be 252 Atk/4 SAtk/252 Spe (if using Hydro Pump) or 4 HP/252 Atk/252 Spe (if using Razor Shell).
Hidden Power (Ice/Fire) should go over Charge Beam or Flash Cannon, as the former type hits Dragonite, Salamence, Gliscor and Landorus hard; the latter hits Scizor, Forretress and Ferrothorn. But then again, Magnezone can use the latter 3 'mons as setup bait for Charge Beam, so yeah. EV spread should be 36 HP/252 SAtk/220 Spe.
Hyper Beam style moves are terrible competitively; as I've said many times before this, it leaves the user as a sitting duck the next turn. Staraptor should be using:
-Return/Double-Edge
-Brave Bird
-Close Combat
-U-turn
Nature: Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Choice Band/Choice Scarf/Life Orb
But then again, Scizor is a better scout than Staraptor because of its lack of a Stealth Rock weakness:
-U-turn
-Bullet Punch
-Superpower
-Pursuit/Quick Attack
Nature: Adamant
EVs: 248 HP/252 Atk/8 Spe
Item: Choice Band
Ability: Technician