Okay, I will answer this, I see some stuff that can make this Team blow, ruining you for the match. Looking at the Team, you seem to struggle with Taunters such as Crobat, Sableye, Whimsicott etc.. If you make a Stall Team, you need to make sure you aren't so susceptible to Taunt, otherwise you will fail in the long run. Just a short blob I wanted to say.
One thing I find odd is that you're running him with no fear of Crobat, who demolishes this Team once Tornadus is done. I suggest trying out Sableye, because it can ruin Crobat with Will-O-Wisp, ruin other Stall Teams with Taunt, and fulfill the Fighting guard for Snorlax. Sableye also gets Recover, so no need for ResTherapy here. Suggested Moveset:
Sableye (F) @ Leftovers
EVs: 252 HP / 252 Def / 4 SDef (Can be changed)
Impish Nature (+Def, - SAtk)
- Foul Play/Shadow Sneak (Think it gets that xD)
Okay, the Set is pretty staright forward. Taunt ruins Crobat mainly, but stops other Stall Teams to avoid many stall wars. Will-O-Wisp burns Physical Pokemon to help with Snorlax, like Cofagrigus, but also burns the Levitating and Flying Type Pokemon, who avoid Toxic Spikes(Added later). Recover does what it says, duh. Foul Play nails those Physical Fire Types who can't be burned, for a liekly KO. Shadow Sneak is nice in that it gets Priority, making for a cool Revenge Killer ^^
Things to look out for with this Poke: Mainly Special Sweepers, Xatu, and Fire Types in Arcanine and Darmanitan.
It seems to fit the whole stall Phazer, so I say keep it as is. But replace Body Slam with Return, because with the extra power, magic happens. The Parahax isn't important here really, as Stall Teams mostly involve Poison as the main status, and sometimes Burn. Form the core of Sableye and Snorlax.
I like Roserade here, but I suggest you try something just for synergy purposes. Roserade has a niche as a Toxic Spiker with the high Speed. You'd think I'd suggest to change the Moveset to Toxic Spiker right? No no. As said, synergy ultimately calls for Nidoqueen as the superior Toxic Spiker for this Team. Tanking Rock and Electric hits for Tornadus to wreck, while hitting real hard with Sheer Force. Thi is what is suggested:
Nidoqueen (F) @Black Sludge
Trait: Sheer Force
EVs: 252 HP / 192 Def / 64 SDef/SAtk
Bold Nature (+Def, -Atk)
- Toxic Spikes
- Earth Power
- Ice Beam
- Dragon Tail/Flamethrower
This is it. Toxic Spikes is the crux of the Set here, spreading Toxic Poison in the opponents Team. With Ground Types, Levitators, and other annoying crap roaming in UU, lets suprise them with Ice Beam. This set leaves the Team vulnerable to Bronzong, I know. Anyway, Earth Power is the Queens best Special STAB, getting a boost from Sheer Force. Ice Beam nails Gligar, Claydol, Flygon, and other things for supereffective damage. Not to mention it gets the Sheer Force boost. Dragon Tail spreads the Toxic poison around the opponents Team. If you prefer to nail some major Pokes like Bronzong, feel free to try Flamethrower, which gets a Sheer Force Boost as well! Nidoqueen better forms your Team synergy so far.
I suggest replacing this guy. We got two Pokes who are inclined to take Physical Hits already. I suggest a Physical Sweeper here. Bisharp is getting replaced too, so we need someone to fill the void. Tornadus brings priority Rain no? Lets add Kingdra then! SS Kingdra is always a Threat, who can also stall Poison with Subsitute+Dragon Dance. Plus, it is the only Physical Sweeper who would do well here. This is what I suggest:
Kingdra (M) @Leftovers
Trait: Swift Swim
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Dragon Dance
Standard Set here. It doesn't even need the Rain to function well here! Substitute guards Kingdra, allowing to use Dragon Dance easier, while helping with the Toxic Stall. Dragon Dance ups Attack and Speed, making Kingdra a deadly Sweeper than it is already. Waterfall and Outrage are STABs. Swift Swim is to be used with the Rain that Tornadus will deliver. But we won't make this a Rain Team :P It helps with the stalling by making Kingdra faster.
As said, this guy is going to be replaced. I feel that Bronzong can help with this Team by providing Hazards. Being that we have a Dragon and Ice Weakness now, lets have Bronzong tank those hits. Bronzong also has Levitate to help with Nidoqueen's Ground Weakness. This is what I recommend here:
Bronzong @Damp Rock/Leftovers
EVs: 252 HP / 4 Def / 252 SDef
Sassy Nature (+SDef, -Spd)
- Stealth Rock
- Rain Dance
- Gyro Ball/Psychic
This seems a bit odd right? Well, let me explain. We made Bronzong more imclined to take Specially Defensive hits here, because we have Nidoqueen and Sableye taking hits on the Physical side. Stealth Rock makes Snorlax's phaze easier by damaging the opponent. Bulldoze seems odd, but we can use the Speed Drop to our advantage... Hell, go with Earthquake if you want xP Rain Dance helps in Kingdra's Sweep, and makes Tornadus more threatening. Damp Rock increases the time the Rain lasts. Gyro Ball or Psychic can be used as STAB, your choice. Seems good so far to me.
I want to keep this guy here, mostly because it gets Priority Subsitute and Rain Dance. Knowing that, we are going to change the Moveset to this:
EVs: 4 Def / 252 SAtk / 252 Spd
Modest Nature (+SAtk, -Atk)
- Rain Dance
- Focus Blast
Typical Moveset here, need I explain it?
This is my view of a better Team, hope you like :P