It's better that you have the EV spreads right at this very moment. I'm afraid you have to do some re-breeding on your Pokémon:
Let's face it; Charizard plain sucks in OU because of its 4x Stealth Rock weakness. While Volcarona also shares that weakness, it hits harder than Charizard does:
-Quiver Dance
-Fire Blast/Fiery Dance
-Bug Buzz
-Giga Drain/Hidden Power (Ground)
Nature: Timid/Modest
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb/Lum Berry
or
-Quiver Dance
-Fiery Dance
-Bug Buzz
-Roost
Nature: Timid
EVs: 240 HP/252 Def/16 Spe
Item: Leftovers
or
-Quiver Dance
-Fire Blast/Fiery Dance
-Bug Buzz
-Rest
Nature: Modest
EVs: 160 HP/236 SAtk/116 Spe
Item: Chesto Berry
Mixed Lucario seems tempting, but it's tricky to split its offensive EVs. It's better off all-physical or all-special:
-Swords Dance
-Close Combat
-ExtremeSpeed
-Ice Punch/Crunch/Shadow Claw/Bullet Punch
Nature: Adamant/Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Life Orb
or
-Nasty Plot
-Aura Sphere
-Dark Pulse/Shadow Ball
-Vacuum Wave/Hidden Power (Ice)
Nature: Modest/Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Life Orb
In order for Zoroark to be on the team, you need someone on the team who can disguise it as something that can take Bug or Fighting moves (because Illusion makes Zoroark take on the appearance of the teammate in the last team slot, and it wears off if Zoroark gets it). Volcarona should be in the last slot of the team, since it resists both Bug and Fighting moves. Zoroark's moves need switching around. Aerial Ace doesn't serve any purpose besides hitting Fighting types super effectively, and a unSTABed neutral Focus Blast does as much as an unSTABed super effective Aerial Ace. U-turn doesn't see use unless Zoroark is Choiced. Adamant is a terrible nature on Zoroark, since it wastes away its excellent Special Attack:
-Sucker Punch
-Low Kick
-Flamethrower
-Dark Pulse/Hidden Power (Ice)
Nature: Naughty
EVs: 200 Atk/92 SAtk/216 Spe
Item: Life Orb
or
-Dark Pulse
-Focus Blast
-Flamethrower/Hidden Power (Ice)
-Trick/U-turn
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Choice Specs/Choice Scarf
or
-Swords Dance
-Sucker Punch
-Low Kick
-Flamethrower/Night Slash
Nature: Naughty
EVs: 252 Atk/40 SAtk/216 Spe
Item: Life Orb
or
-Nasty Plot
-Dark Pulse
-Focus Blast
-Substitute/Flamethrower
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Life Orb/Focus Sash
Eelektross may seem tempting to use because of its lack of weaknesses and wide movepool, but it's just too slow. Rotom-W or Jolteon should replace it, as both are faster:
Rotom-W:
-Volt Switch
-Hydro Pump
-Will-o-Wisp
-Pain Split/Hidden Power (Ice)
Nature: Modest
EVs: 232 HP/56 SAtk/220 Spe
Item: Leftovers
or
-Volt Switch
-Hydro Pump
-Thunder Wave/Will-o-Wisp
-Pain Split
Nature: Calm
EVs: 248 HP/28 SAtk/232 SDef
Item: Leftovers
or
-Volt Switch
-Hydro Pump
-Hidden Power (Ice)
-Trick/Thunderbolt
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Choice Specs/Choice Scarf
Jolteon:
-Thunderbolt
-Volt Switch
-Signal Beam
-Hidden Power (Ice)
Nature: Timid
EVs: 4 Def/252 SAtk/252 Spe
Item: Life Orb/Choice Specs
Ability: Volt Absorb
Hydreigon has a massive movepool, but some coverage moves are better to use than others:
-Draco Meteor
-Fire Blast
-Superpower
-Roost/Earthquake/Earth Power/Dark Pulse
Nature: Rash/Mild
EVs: 4 Atk/252 SAtk/252 Spe
Item: Expert Belt/Life Orb
or
-Substitute
-Dragon Pulse
-Focus Blast
-Fire Blast/Roost
or
-Draco Meteor
-Focus Blast
-Fire Blast/Flamethrower
-U-turn/Dark Pulse
Nature: Modest
EVs: 4 HP/252 SAtk/252 Spe
Item: Choice Specs
Since you have a Pokémon extremely vulnerable to Stealth Rock, a Rapid Spinner is pretty much mandatory to get said hazard off the field. Starmie fills that slot in nicely:
-Hydro Pump/Surf
-Psyshock/Thunderbolt
-Ice Beam/Recover
-Rapid Spin
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Leftovers/Life Orb
Ability: Natural Cure
or
-Scald
-Rapid Spin
-Psyshock/Ice Beam/Thunderbolt
-Recover
Nature: Timid
EVs: 248 HP/36 Def/224 Spe
Item: Leftovers
Ability: Natural Cure