Competitive Team Building: Help!

Hello everyone! Need some help in regards of team building, item equipping, movesets and what Pokémon to use in each team to create good synergy. Just so you all know, I've only recently (past month) gotten into competitive battling and training my Pokémon to their potential. Feel free to recommend me new Pokémon to use!

These are the Pokémon I have EV trained so far:

Charizard Shiny (F) @ Mega X
Nature Adamant
Ability Blaze
6 IV ~ EV 252 Attack / 252 Speed / 4 Defense
Moveset Flare Blitz / Outrage / Flamethrower / Dragon Dance

Tyranitar (F) @ ???
Nature Adamant
Ability Sand Steam
6 IV ~ EV 252 Attack / 252 Speed / 4 HP
Moveset Crunch / Dragon Dance / Stone Edge / Earthquake

Greninja Shiny (M) @ ???
Nature Timid
Ability Protean
6 IV ~ EV 252 Speed / 252 Sp. Attack / 4 HP
Moveset Dark Pulse / Grass Knot / Ice Beam / Scald

Dragonite (F) @ ??? <-- or Dragon Plate?
Nature Adamant
Ability Multiscale
6 IV ~ EV 252 Attack / 252 Speed / 4 Defense
Moveset Extreme Speed / Dragon Dance / Outrage / Dragon Rush

Reuniclus Shiny (F) @ Life Orb
Nature Quiet
Ability Magic Guard
6 IV ~ EV 252 HP / 252 Sp. Attack / 4 Defense
Moveset Trick Room / Psychic / Focus Blast / Shadow Ball

Togekiss (F) @ ???
Nature Modest
Ability Serene Grace
6 IV ~ EV 252 Sp. Attack / 252 Speed / 4 Defense
Moveset Air Slash / Roost / Aura Sphere / Toxic

Togekiss Shiny (F) @ ???
Nature Modest
Ability Serene Grace
6 IV ~ EV 252 Sp. Attack / 252 Speed / 4 Defense
Moveset Air Slash / Roost / Aura Sphere / Defog

Charizard (M) @ Mega Y
Nature Modest
Ability Blaze
6 IV ~ EV 252 Sp. Attack / 252 Speed / 4 Defense
Moveset Flamethrower / Solar Beam / Dragon Pulse / ???

Typhlosion Shiny (F) @ ??? <-- or Rocky Helmet?
Nature Timid
Ability Blaze
6 IV ~ EV 252 Sp. Attack / 252 Speed / 4 Defense
Moveset Eruption / ??? / ??? / ???

Garchomp (F) @ Garchompite
Nature Adamant
Ability Rough Skin
6 IV ~ EV 252 Attack / 252 Speed / 4 HP
Moveset Earthquake / Dragon Rush / Rock Slide / Flamethrower

Latios (M) @ ??? <-- or Latiosite when it's released
Nature Timid
Ability Levitate
6 IV ~ EV 252 Sp. Attack / 252 Speed / 4 Defense
Moveset Psychic / Recover / Dragon Dance / Surf or Ice Beam

Ampharos Shiny (F) @ Ampharosite <-- possible Dragon Tank?
Nature Modest
Ability Plus
6 IV ~ EV 252 Sp. Attack / 252 HP / 4 Defense
Moveset Dragon Pulse / Lightscreen / Confuse Ray / Thunder

Milotic (F) @ ???
Nature Bold
Ability Marvel Scale
6 IV ~ EV 252 HP / 252 Defense / 4 Sp. Defense
Moveset Ice Beam / Recover / Scald / Toxic

Mawile Shiny (F) @ Mawalite
Nature Adamant
Ability Sheer Force
6 IV ~ EV 252 HP / 252 Attack / 4 Defense
Moveset Iron Head / Swords Dance / Sucker Punch / Play Rough

Manectric (F) @ Manectite
Nature Timid
Ability Static
6 IV ~ EV 252 Sp. Attack / 252 Speed / 4 HP
Moveset Thunderbolt / Flamethrower / Volt Switch / Signal Beam

Arcanine (F) @ ???
Nature Jolly
Ability Intimidate
6 IV ~ EV 252 Attack / 252 Speed / 4 HP
Moveset Extreme Speed / Flare Blitz / Wild Charge / Close Combat

Blastoise (M) @ ???
Nature Bold
Ability Rain Dish
6 IV ~ EV 252 Sp. Attack / 252 HP / 4 Sp. Defense
Moveset Rapid Spin / Scald / Dragon Tail / Toxic

Xatu (F) @ Light Clay
Nature Timid
Ability Magic Bounce
6 IV ~ EV 252 HP / 252 Speed / 4 Defense
Moveset Future Sight / Wish / Reflect / Light Screen or U Turn

I'll be training also a Blissey, Mega Lucario, Absol, Blaziken and Amaura. Note also that the Pokémon who can mega evolve and have @ ??? by their name means that I don't want to ideally mega them. Thank you!

 

I think Reuniclus is better off with Life Orb, since she gets no recoil damage from it and has more strength in her attacks.