Here is the team so far:
Tapu Koko @ Light Clay
Ability: Electric Surge
EVs: 248 HP / 8 Def / 252 Spe
Jolly Nature
- Reflect
- Light Screen
- Taunt
- U-turn
The lead. Light Clay makes Reflect and Light Screen last for eight turns. U-Turn to deal some damage and switch out. I like it because its really fast with a stat of 394 at max.
Hawlucha @ Electric Seed
Ability: Unburden
EVs: 252 Atk / 24 Def / 116 SpD / 116 Spe
Adamant Nature
- Acrobatics
- High Jump Kick
- Poison Jab
- Swords Dance
Hawlucha is to come directly after Tapu Koko and use Electric Seed to activate Unburden. Acrobatics deal 2x damage after Electric Seed is consumed. High Jump Kick gains STAB and does high damage. +2 High Jump Kick can also OHKO or 2OHKO Ferrothorn. Poison Jab is to cover the fairy type weakness. And Tapu Koko's dual Screen support means it can certainly tank a hit or two and set-up with Swords Dance.
Victini @ Normalium Z
Ability: Victory Star
EVs: 80 HP / 252 SpA / 176 Spe
Modest Nature
IVs: 0 Atk
- Celebrate
- Stored Power
- Searing Shot
- Thunderbolt
Z-Celebrate boosts Victini's all stat by 1 level, making Stored Power of base 110 and gains STAB. Searing Shot gets STAB and has 30% chance of burning. I'm not sure whether running Blue Flare is better, so need advice on that. Thunderbolt for Water-types.
Hoopa-Unbound @ Kee Berry
Ability: Magician
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Destiny Bond
- Psychic
- Dark Pulse
- Nasty Plot
Not much to say.... I'm not sure whether to run it or not....
Excadrill @ Focus Sash
Ability: Sand Rush
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Iron Head
- Stealth Rock
- Rapid Spin
- Earthquake
Iron Head gains STAB and good chance of flinching. Stealth Rock hurts foes on switch-in and helps against Sash mons. Rapid Spin frees me from hazards without clearing mine's. Stealth Rocks are certainly a threat for Mega-X, so Rapid Spin is mandatory. Earthquake does decent damage and STAB.
Charizard-Mega-X @ Charizardite X
Ability: Tough Claws
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Dragon Dance
- Flare Blitz
- Earthquake
- Roost
DD Setup sweeper. Flare Blitz from Tough Claws does a whooping 156 damage. +1 Earthquake OHKOs Toxapex while Flare Blitz certainly counters Assault Vest Magearna, which is a threat for Victini. Earthquake also gives much more coverage than Dragon Claw. And Roost to heal yourself.