According to the vr, Marshadow is A+ rank which means its very strong in the tier while Pheromosa is only C, the niche ranks. And based on their analysis pages, they can run the following sets
Marshadow @ Life Orb
Ability: Technician
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Spectral Thief
- Low Kick
- Shadow Sneak
- Ice Punch
Marshadow @ Choice Band
Ability: Technician
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Spectral Thief
- Low Kick
- Shadow Sneak
- Ice Punch
Pheromosa @ Choice Band
Ability: Beast Boost
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- U-turn
- Close Combat
- Throat Chop
- Triple Axel
Lastly, take those sets from the analysis pages with a grain of salt. They might not be fully up to date with the current uber metagame