Cloyster @ Focus Sash
Ability: Skill Link
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Shell Smash
- Razor Shell
- Icicle Spear
- Protect

Tapu Bulu @ Life Orb
Ability: Grassy Surge
Level: 50
EVs: 244 HP / 116 Atk / 140 Def / 4 SpD / 4 Spe
Adamant Nature
- Swords Dance
- Horn Leech
- Stone Edge
- Protect

Clefairy @ Eviolite
Ability: Friend Guard
Level: 50
EVs: 220 HP / 172 Def / 116 SpD
Sassy Nature
IVs: 0 Atk / 0 Spe
- Follow Me
- Moonblast
- Encore
- Protect

Magnezone @ Choice Specs
Ability: Magnet Pull
Level: 50
EVs: 12 HP / 4 Def / 244 SpA / 4 SpD / 244 Spe
Modest Nature
IVs: 0 Atk
- Hidden Power [Ground]
- Thunderbolt
- Volt Switch
- Flash Cannon

Arcanine @ Sitrus Berry
Ability: Intimidate
Level: 50
EVs: 252 HP / 124 Def / 4 SpA / 28 SpD / 100 Spe
Modest Nature
IVs: 0 Atk
- Burn Up
- Snarl
- Will-O-Wisp
- Helping Hand

Garchomp @ Groundium Z
Ability: Sand Veil
Level: 50
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Swords Dance
- Earthquake
- Poison Jab
- Protect

Changed the move sets a bit. I went with Swords Dance over Wood Hammer on Bulu because I started with a Z-Rock variant for luring and OHKOing Celesteela at +2. You can certainly change it. Also take 4 EVs out of SpD and put them in Spe because 4 and 8 EVs give the same stat, so you lose nothing and gain a point of speed creep.

I made Cloyster a shell smash set, you don't need rapid spin because hazards don't really exist in VGC. I prefer STABs + protect but there is a place for Rock Blast I guess. One cool thing is that boosted Cloyster always OHKOs Kartana which is really nice.

Next I added Clefairy for redirection support, because with Friend Guard Tapu Bulu becomes really bulky, and follow me can allow the two free turns to set up some stat boosts. Moonblast is purely for not being 100% taunt bait and for fishing for SpA drops on a switch or something. Encore is essentially just for helping the Trick Room match up, which is also why I made Clefairy min speed.

Magnezone hits like an absolute monster. It is EVed to speed creep common Tapu Fini sets and always OHKO them with Thunder Bolt. It is also faster than max speed Marowak (which does exist sometimes, don't ask me why) and the fastest Celesteela I've seen. It can trap in Celesteela and OHKO it to avoid late game stall shenanigans. Volt Switch does respectable damage and can help you manage board position. Flash Cannon OHKOs Tapu Lele and Bulu (most of the time) which is good. HP Ground doesn't OHKO opposing Marowak but a combination of that and snarl will. HP can also be used against Magnezone for an OHKO which is good, and it serves as a really good switch in for poison moves aimed at Bulu or Clefairy.

Arcanine brings Intimidate support as well as a plethora of support options. I'm partial to Burn Up as the fire move because I find myself switching it a lot anyways for intimidate cycling. Flamethrower is also an option. Arcanine does well against Kartana, and it can burn physical attackers to slow them down. Snarl chips and lowers SpA and helping hand lets you get the extra damage you need for KOs sometimes. Though those two last moves are certainly easily adaptable. You also can experiment and figure out if you prefer flamethrower over Burn Up. The EVs make opposing Garchomp's earthquake a 3hko with sitrus after Intimidate. With Grassy Terrain it's not a concern at all, so you can try Figgy/Iappa or one of those berries if you want.

Garchomp is the last edition to the team and the least polished. I like swords dance because it can abuse Clefairy's support as well. It's pretty standard, and the ability can go either way. I just went with Sand Veil on the off chance that you can RNG your way to victory against sand teams.