So this is a revised version
Hydreigon @ choice scarf
Ability: Levitate
Nature: Timid
EVs: 252 SpA/Spd 4 Hp
Draco Meteor
Flash cannon
Focus blast
Flamethrower
Reliable switch in sweeper, fairy check, paired with Muk and it goes down, Muk gets Levitate, no weakness. Focus blast coverage(if it hits)
Alolan Muk @ Normalium Z
Ability: Power of Alchemy
Nature: Careful
EVs: 252 Hp/SpD 4 Def
Gunk shot
Stockpile
Shadow sneak
Knock off
Special Wall, knock off for annoying held items, shadow sneak priority, fairy counter, z Stockpile sustain
Tyranitar @ Assault vest
Ability: Sandstream
Nature: Impish
EVs: 252 SpD 158 Hp 100 Def
Stone edge
Thunder fang
Payback
Earthquake
Physical sweeper, ground coverage is always good. Thunder fang coverage, payback STAB plus it's very likely it won't move first
Yveltal @ Big root
Ability: Dark Aura
Nature: Timid
EVs: 252 SpA/Spd 4 Hp
Oblivion Wing
Taunt
Dark pulse
Tailwind
Support(especially with dark Aura +33%) set up shut down.
Greninja @ choice specs
Ability: Protean
Nature: Timid
EVs: 252 SpA/Spd 4 Hp
Scald
U turn
Dark pulse
Ice beam
Scout, special sweeper option, takes care of all fire types that can't be will o wisp. Plus burn chance. And possibly flinch support
Sableye @ Sablenite
Ability: Prankster/Magic Bounce
Nature: Calm
EVs: 252 Hp 156 Def 100 SpD
Snarl
Recover
Calm mind
Will o wisp
Physical wall, physical shut down, special debilitater, stall, hazard reflect, best mega for this spot hands down
What do you think? Any further improvement?