Okay, so I am sorry to say that your team did not meet VGC standards very well. It is a great singles team, but will fail in doubles (VGC). Out of all your Pokemon, Mega Charizard Y is the only Pokemon that sees the light of day in VGC. So I wrote you an entirely new team, and I hope you like it. By the way, when you have EV sets its 252/252/4 instead of 252/252/6. If you do not like it, or really want a certain Pokemon in your lineup, comment which ones you want and I can edit you a new one.
The Team:
Gyarados @ Gyaradosite
Ability: Intimidate --> Mold Breaker
EVs: 36 HP / 148 Atk / 44 Def / 84 Sp. Def / 196 Spe
Adamant Nature
Waterfall
Ice Fang
Earthquake
Protect
Volcarona @ Charti Berry
Ability: Flame Body
EVs: 252 HP / 36 Def / 4 SpA / 4 SpD / 212 Spe
Modest Nature
Quiver Dance
Heat Wave
Bug Buzz
Giga Drain
Landorus-Therian @ Assault Vest
Ability: Intimidate
EVs: 252 Attack, 252 Speed, 4 HP
Adamant Nature
Superpower
Earthquake
Rock Slide
U-Turn
Lucario @ Lucarionite
Ability: Inner Focus --> Adaptability
EVs: 252 Special Attack/ 252 Speed/ 4 HP
Timid Nature
Flash Cannon
Aura Sphere
Protect/ Hidden Power (Ice)
Follow Me
Aegislash @ Life Orb
Ability: Stance Change
EVs:252 HP/ 76 Special Defense/ 180 Special Attack
IVs: 0 Speed
Quiet Nature
Flash Cannon
Shadow Ball
King's Shield
Wide Guard
Dragonite @ Sitrus Berry/Lum Berry
Ability: Mulitiscale
EVs: 204 HP / 32 Def / 4 Atk / 16 SDef / 252 Spd
Jolly Nature
Extreme speed
Dragon Claw
Protect
Roost
Overview:
This team balances very nicely, when plugged into a team builder you do not have any over lying weaknesses. So lets begin. All of these Pokemon have serious power, and can all pick-up several KO's.
I opted for two megas as two megas is always useful. When you take a look at the other team and see that it is opposing to one of your Megas, you can always use the other one. Use your better knowledge about which Mega to use in certain matches! So the breakdown of this team is the 2 Intimidate users, one of which will Mega evolve sometimes, which helps keep your team safe. Pokemon like Volcarona appreciate the pseudo bulk, as they have low defense. Aegislash is your trick room counter, as the rest of your Pokemon are pretty or very fast.
Your leads can be:
Volcarona + Lucario
Mega Gyarados + Dragonite/ Landorus
Dragonite + Landorus (This one creates a nasty ice weakness, if the opponent has water or ice Pokemon, I wouldn't recommend this)
I prefer Volcarona and Lucario. Lucario uses Follow Me in order to Protect Volcarona while he sets up with one of the best boosting moves in the game, Quiver Dance. After that you can proceed to sweep. However Follow Me will not protect Volcarona from Rock Slide which is 4x effective on him, which is why the Charti Berry is used so he can survive. They all have custom EV sets in order to survive the most common hits from the most common Pokemon in VGC. I personally think all of the sets on the Pokemon are fairly standard, I did use Special Lucario, so that your team is balanced with 3 Special and 3 Physical. Furthermore, Ice Fang was used on Gyarados to deal with the common Dragon and flying Pokemon, although Crunch would be a good also as it gets STAB in his Mega form. I think this team will hold up very well in VGC. I'm sorry if I made too many changes but I hope you enjoy your new doubles team.
Also if your okay with breeding alot, shiny Gyarados, Aegislash,Lucario and Volcarona are very cool shiny haha :)
Good Luck! Hope you liked it!
-The Love Child of VGC and Pokemon
(Unstoppable)