Meloetta:

Nice Meloetta you got there, but the only problem is that you have the wrong Forme for this to really shine. Replace Perish Song with Relic Song to change its Forme to the sweeper Type. After that, I suggest this Meloetta:
Meloetta@ Expert Belt
Trait: Serene Grace
EVs: 252 Attack, 4 Sp. Attack, 252 Speed
Hasty Nature:(-Defense +Speed)
- Relic Song
- Close Combat
- Shadow Claw
- Stone Edge
This takes advantage of Meloetta-P's Stats and potential. Relic Song changes Forme. Close Combat is STAB, Shadow Claw covers Psychic Types and paired with Serene Grace, you will be getting a lot of Critical Hits. Stone Edge is for Flying Types. Use this well
Crobat:

I don't like this Crobat, honestly. It is outclassed at Special Sweeping by:

Venomoth
You should roll with Venomoth, because it gets the coveted Quiver Dance move, which can either be Baton Passed or utilized. Here is my suggested Venomoth:
Venomoth@ Black Sludge
Trait: Tinted Lens
EVs: 4 HP, 252 Sp. Attack, 252 Speed
Timid Nature:(-Attack +Speed)
- Sleep Powder
- Quiver Dance
- Baton Pass
- Bug Buzz
Here it is. Sleep Powder puts the foe to sleep, which allows a few Quiver Dances to be set up. You can either Baton Pass it to a good Sweeper, or start a Sweep with an unresisted Bug Buzz.
Weavile:

Standard Weavile, replace the Ability Pickpocket for Pressure because Pickpocket is useless. After that, give Weavile a Life Orb to strengthen Power. Replace Ice Punch with Ice Shard because it gets priority
Roserade:

Honestly, I don't like this Roserade Moveset, and since you need Entry Hazard Support, I suggest this Roserade:
Roserade@ Leftovers
Trait: Natural Cure
EVs: 252 HP, 120 Defense, 136 Sp. Defense
Calm Nature:(-Attack +Sp. Defense)
- Spikes
- Giga Drain
- Sludge Bomb
- Rest
This is the most annoying Roserade ever to battle. Spikes supports your Team with Entry Hazards. Giga Drain is STAB and recovers HP with Sludge Bomb is STAB with a Nice chance to cause Poison. Rest recovers HP to full health and if you switch out and back in, Roserade will not have the Sleep Status. Use it well.
Empoleon:

This Empoleon is okay, but is really Outclassed by one Pokemon. That Pokemon is the one I'm suggesting to replace Empoleon. That Pokemon is:

Azumarill
Huge Power really makes Azumarill one of the deadliest Sweepers in UU because of its Ability, Huge Power which Doubles Attack. Here is the Azumarill I suggest:
Azumarill@ Choice Band
Trait: Huge Power
EVs: 252 HP, 252 Attack, 4 Speed
Adamant Nature:(-Sp. Attack + Attack)
- Aqua Jet
- Superpower
- Ice Punch
- Waterfall
This is it, Azumarill. Aqua Jet coming from this Azumarill is as strong as Scizor's Bullet Punch. Superpower is coverage and pairs nice with Huge Power. Ice Punch covers Grass Types really well. Waterfall is STAB when you know you will outspeed your opponent. Azumarill also has amazing synergy with Roserade, who helps Azumarill with Electric Types and Bulky Water's, which trouble Azumarill.
Typhlosion:

Don't try to run a Sunny Day Moveset on such a frail Pokemon. I suggest this Moveset:
- Eruption
- Hidden Power Grass
- Focus Blast/Extrasensory
- Flamethrower
This is the most dangerous Typhlosion. Eruption causes immediate massive damage. Hidden Power Grass covers all of your weaknesses. Focus Blast and Extrasensory are coverage, your choice. In case your HP is down enough that Eruption can't be used, Flamethrower is there as a substitute. The recommended Item is Choice Specs with a Timid Nature, or a Choice Scarf with a Modest Nature.
Good luck with your Team :)
-Mike