Not Ring Target'd
Fan Rotom@Ring target
EV: 252HP, 252Sp. Att, 4 Def or Spdef
Ring Target would normally cancel its holder's immunity. But Fan Rotom has leviatate, so even if its flying type immunity is cancel, its ability will still block ground attacks. Against flying-type pokemon, use trick and your partners can EQ all they want. Or you can use trick on ground foes to paralyze them.
Discharge hits all foes, but at the price of hitting your allies too. Thunder has the same chance of paralyzing as discharge with 30%, but it has more power. Better to be used in rain dance team though. Finally, T-wave sacrifices power for a guaranteed par.
Air Slash and Hex are offense options. The former helps flinch while the latter takes advantage for par.
Finally, the last slots involves confusion to minimize the chanse of your foe attacking. As mentioned earlier, CR is more stable while Swagger helps chip HP off. If you're onto stopping foes from using moves, use Aire Slah and CR. If you're onto offence, use swagger.
With 86 base speed and the lack of choice scarf, fan rotom might not be able to outrun sweepers with thunderwave regardless of EVs. Therefore, I took the bulkiness approach.