Arcanine/Fini/Kartana/Garchomp/Koko/Muk

#1
Arcanine @ Sitrus Berry
Ability: Intimidate
Level: 50
EVs: 148 HP / 4 Def / 164 SpA / 28 SpD / 164 Spe
Timid Nature
IVs: 0 Atk
- Will-O-Wisp
- Flamethrower
- Snarl
- Protect

Garchomp @ Groundium Z
Ability: Rough Skin
Level: 50
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Earthquake
- Rock Slide
- Poison Jab
- Protect

Tapu Koko @ Life Orb
Ability: Electric Surge
Level: 50
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Thunderbolt
- Discharge
- Dazzling Gleam
- Protect

Kartana @ Assault Vest
Ability: Beast Boost
Level: 50
EVs: 116 HP / 4 Atk / 4 Def / 132 SpD / 252 Spe
Jolly Nature
- Leaf Blade
- Smart Strike
- Sacred Sword
- Night Slash

Tapu Fini @ Leftovers
Ability: Misty Surge
Level: 50
EVs: 252 HP / 44 Def / 196 SpA / 4 SpD / 12 Spe
Calm Nature
IVs: 0 Atk
- Muddy Water
- Moonblast
- Calm Mind
- Protect

Muk-Alola @ Figy Berry
Ability: Gluttony
Level: 50
EVs: 188 HP / 244 Atk / 44 Def / 20 SpD / 12 Spe
Adamant Nature
- Poison Jab
- Knock Off
- Curse
- Protect
 
#2
Well, you have no resistances to ground, and half your team is weak to it. I reccomend a Porygon2 somewhere in there to ice beam garchomp.
 
#3
the team is just the top 5 most used pokemon and i was going to use the top 6 but then i would have Tapu Koko, Fini, and Lele and while double Tapu is nice i think 3 or 4 Tapus while likely would a good idea is a little extreme, but that would explain why on the Global Link Garchomp defeats almost all of the top 30 used pokemon because it is common and a lot of ground weak pokemon are really good in the current meta
 
#4
So, what is each pokemon supposed to do for each other? What do the EV spreads do? How do they synergize with each other? It's kind of hard to see where this team is going with just "this is the top 5 most used Pokemon + Garchomp" as the only explanation. What have you been struggling with in testing? (The common ground-weakness among most of the team as mentioned by R-B-Y is definitely an issue that could be better addressed, as I am guessing it is one of the main issues.) What on the team is working and what isn't working? We need more info to provide better feedback.