Damn, so many metagross users in the league. Goodluck to leaders :v
It seems like the only type your team cant cover up is normal types. When someone says normal type, first thing you should think is stall (Cuz chansey/porygon2/cancerous ditto)
My suggestion would be adding at least 1 fighting type move.(Or pokemon, u can replace the coverage)
Other than that, mandibuzz is quite passive versus pokemons like mega scizor, mega metagross that can set up freely with this moveset. (Some metagross that runs agility will outspeed your salazzle, metagross just wins the game after salazzle is down.) I'D say you need foul play in your team 100%.
As for rotom, discharge is a quite risky move, only good use of it would be with garchomp, they make a solid duo in doubles. One is immune to ground, other is immune to electric. But once one of them is down, you probably shouldnt use discharge ever, and garchomp wont last long for sure. You should replace with volt switch perhaps, you would get the momentum you need.
Other than the coverage issues, your team seems quite weak in double teams, I'd suggest you to get a wide guard user. ( I also suggested a fighting type pokemon, maybe hitmontop will work w/ intimidate )