Just fyi, this is my first year attempting to do VGC (or any type of competitive pokemon). I've been playing on Pokemon Online and trying different teams and combos and this is the best I've been able to get so far, so RMT.
I'm waiting to actually RNG and train the pokemon in my actual game until I have a team that's rated well and works well on Pokemon Online
THE POINT OF THIS TEAM IS TO HIT FIRST AND KO THEM BEFORE THEY HAVE A CHANCE TO ATTACK. I really hate when people take an RMT and suggest changing the nature/Ev's that support the team's strategy. If the strategy is bad, say that, but don't change it and still keep this strategy as a suggestion..
Mienshao @ Life Orb
Jolly Nature (+Speed, -Sp. Atk)
+252 Speed/+252 Attack/+4 HP
-Fake Out
-Hi Jump Kick
-Rock Slide
-Drain Punch
My first lead, Menshao ("Farfetch'd 2"), leads with fake out unless it doesn't make sense to. Then whichever is better, Rock Slide or High Jump Kick, I use. Also, due to his ability he can not flinch, so he can not be Faked Out
Hi Jump Kick if I doubt they'll use protect and my HP is high, Drain Punch if there's a chance for Protect or my HP is low (unless the difference in power will KO them)
Chandelure @ Focus Sash
Timid Nature (+Speed, -Atk)
+252 Speed/+252 Sp. Atk/+4 HP
-Heat Wave
-Shadow Ball
-Energy Ball
-Hidden Power (Ice/70pwr)
My second lead, Chandelure, almost always opens up with heat wave. It's especially good for Amoongusses and Whimsicotts. However Shadow Ball and Energy Ball have also come in handy quite a bit. Psychic, not so much. Being Ghost type, Chandelure can't be faked out, so this means I'm completely immune to Fake-Out openers with this lead team. Focus Sash helps a LOT.
Hydreigon @ Chople berry
Timid Nature (+Speed, -Atk)
+252 Speed/+252 Sp. Atk/+4 HP
-Dragon Pulse
-Dark Pulse
-Fire Blast
-Focus Blast
Hydreigon has fairly quick speed, and as for Haxorus vs Hydreigon, unless Haxorus uses Quick Claw or Focus Sash (or whatever the speed one is), Hydreigon will always outspeed Haxorus. The others are for coverage as well. They all come in handy a bit, but if Dark, Fire, and Fighting aren't going to be super-effective, Dragon Pulse always does a good deal of damage. Chople Berry comes in handy very often.
Terrakion @ Muscle Band/Choice Scarf
Jolly Nature (+Speed, -Sp. Atk)
+252 Speed/+252 Attack/+4 HP
-Close Combat
-Rock Slide
-Earthquake
-Quick Attack
Originally Jellicent, but changed to Terrakion, I've yet to find a strong 4th pokemon -- Terrakion does good but I feel like someone else could do better. Feel free to suggest a good 4th :)
BIG ISSUE: Tailwind (almost always Tornadus). It means I don't go first, and since my guys aren't Defensive, they die quickly. Is there any good way to handle Tail Wind with my opening team? I can Fake Out the guy on the first turn but can only get him to about 30% hp with Fake Out + Heat Wave
I'm waiting to actually RNG and train the pokemon in my actual game until I have a team that's rated well and works well on Pokemon Online
THE POINT OF THIS TEAM IS TO HIT FIRST AND KO THEM BEFORE THEY HAVE A CHANCE TO ATTACK. I really hate when people take an RMT and suggest changing the nature/Ev's that support the team's strategy. If the strategy is bad, say that, but don't change it and still keep this strategy as a suggestion..

Mienshao @ Life Orb
Jolly Nature (+Speed, -Sp. Atk)
+252 Speed/+252 Attack/+4 HP
-Fake Out
-Hi Jump Kick
-Rock Slide
-Drain Punch
My first lead, Menshao ("Farfetch'd 2"), leads with fake out unless it doesn't make sense to. Then whichever is better, Rock Slide or High Jump Kick, I use. Also, due to his ability he can not flinch, so he can not be Faked Out
Hi Jump Kick if I doubt they'll use protect and my HP is high, Drain Punch if there's a chance for Protect or my HP is low (unless the difference in power will KO them)

Chandelure @ Focus Sash
Timid Nature (+Speed, -Atk)
+252 Speed/+252 Sp. Atk/+4 HP
-Heat Wave
-Shadow Ball
-Energy Ball
-Hidden Power (Ice/70pwr)
My second lead, Chandelure, almost always opens up with heat wave. It's especially good for Amoongusses and Whimsicotts. However Shadow Ball and Energy Ball have also come in handy quite a bit. Psychic, not so much. Being Ghost type, Chandelure can't be faked out, so this means I'm completely immune to Fake-Out openers with this lead team. Focus Sash helps a LOT.

Hydreigon @ Chople berry
Timid Nature (+Speed, -Atk)
+252 Speed/+252 Sp. Atk/+4 HP
-Dragon Pulse
-Dark Pulse
-Fire Blast
-Focus Blast
Hydreigon has fairly quick speed, and as for Haxorus vs Hydreigon, unless Haxorus uses Quick Claw or Focus Sash (or whatever the speed one is), Hydreigon will always outspeed Haxorus. The others are for coverage as well. They all come in handy a bit, but if Dark, Fire, and Fighting aren't going to be super-effective, Dragon Pulse always does a good deal of damage. Chople Berry comes in handy very often.

Terrakion @ Muscle Band/Choice Scarf
Jolly Nature (+Speed, -Sp. Atk)
+252 Speed/+252 Attack/+4 HP
-Close Combat
-Rock Slide
-Earthquake
-Quick Attack
Originally Jellicent, but changed to Terrakion, I've yet to find a strong 4th pokemon -- Terrakion does good but I feel like someone else could do better. Feel free to suggest a good 4th :)
BIG ISSUE: Tailwind (almost always Tornadus). It means I don't go first, and since my guys aren't Defensive, they die quickly. Is there any good way to handle Tail Wind with my opening team? I can Fake Out the guy on the first turn but can only get him to about 30% hp with Fake Out + Heat Wave