Taking my first whack at a Competitive Team

Zoroark
Nature: Jolly (+Speed, -S. Atk)
EV Spread: 4 HP, 252 ATK, 252 Speed
Held Item: Focus Sash
Ability: Illusion
Moves: Sucker Punch, U-turn, Knock Off, Taunt

Notes: Serves a specialized role that focuses on disrupting setups and certain held item combinations then quickly getting out. Has a synergy with the "Magic Bounce" Espeon.


Shuckle
Nature: Bold (+Def, -Atk)
EV Spread: 252 HP, 56 Def, 200 S. Def
Held Item: Binding Band
Ability: Contrary
Moves: Wrap, Shell Smash, Encore, Rest

Notes: Somewhat simple Contrary Wall setup with a few tweaks. I took Wrap + Binding Band combo over toxic as it increases the incremental damage from 1/16th to 1/8th (from what I can tell some sources claim it was changed to 1/8th normally in 6th gen but I can't confirm) and took encore as a means of locking out move choices similarly to Zoroark.


Espeon
Nature: Bold (+Def, -Atk)
EV Spread: 144 HP, 114 Def, 252 Speed
Held Item: Leftovers
Ability: Magic Bounce
Moves: Psyshock, Baton Pass, Calm Mind, Wish

Notes: Serves as a stat buffer for the team allowing easier setups for potential stall tactics or sweeps based on the situation while being useful for discouraging status condition usage.


Vaporeon
Nature: Modest (+S. Atk, -Atk)
EV Spread: 252 HP, 132 Def, 126 S. Atk
Held Item: Absorb Bulb
Ability: Hydration
Moves: Surf, Rain Dance, Acid Armor, Rest

Notes: Serves as a tanky Special Sweeper. With Hydration using Rain Dance + Rest frees the held item slot and allows a perpetual chesto-resto combo in essence as long as Raining weather is maintained (added bonus is it makes status conditions less useful against it as they are removed at the end of the turn when its raining).


Garchomp
Nature: Jolly (+Speed, -S. Atk)
EV Spread: 192 HP, 70 Atk, 248 Speed
Held Item: Garchompite
Ability: Rough Skin
Moves: Dual Chop, Earthquake, Shadow Claw, Iron Head

Notes: A tanky Physical Sweeper nothing really special.


Infernape
Nature: Jolly (+Speed, -S. Atk)
EV Spread: 4 HP, 252 Atk, 252 Speed
Held Item: Expert Belt
Ability: Iron Fist
Moves: U-Turn, Mach Punch, Fire Punch, Thunder Punch

Notes: Is kept in the back of the party due to Zoroark's Ability.

Get rid of the special atack evs on zoroark and give it jolly nature instead

Okay I updated the post to take that into account. Thanks for the critique man.