Vikavolt @ Buginium Z  
Ability: Levitate  
EVs: 160 HP / 252 SpA / 96 SpD  
Modest Nature  
IVs: 0 Atk  
- Protect  
- Endure  
- Bug Buzz  
- Substitute

Zeraora @ Fightinium Z  
Ability: Volt Absorb  
EVs: 64 HP / 252 SpA / 192 Spe  
Timid Nature  
- Fake Out  
- Focus Blast  
- Calm Mind  
- Laser Focus  

Rotom @ Ghostium Z  
Ability: Levitate  
EVs: 40 Def / 252 SpA / 216 Spe  
Timid Nature  
IVs: 0 Atk  
- Snatch  
- Hex  
- Will-O-Wisp  
- Pain Split

What they do:

Vikavolt is an extremely slept on pokemon. It beats Electivire, Rotom-Mow, Zeraora, Heliolisk, and 50/50s Stunfisk as well as any FEAR you encounter.

Zeraora beats Manectric-Mega, rotom forms, Magnezone, and Heliolisk and 50/50s Golem-Alola

Rotom is able to 100% Golem-Alola, beat stunfisk, and beat Zeraora.
 
Team Weaknesses:

Vikavolt

Other Vikavolt can prove especially deadly to this team.