OK, heres what I would change about your team
Infernape @Focus Sash
EVs: 252 Atk/ 4 SpDef / 252 Spe
Jolly Nature
- Stealth Rock
- Close Combat
- Flare Blitz
- U-Turn
Infernape has a pretty good speed stat, so it can function as a lead very well, U-Turn is for switching. Mach Punch was pretty much useless as most leads wont outspeed.
Snorlax @ Chesto Berry
Ability: Thick Fat
EVs: 252 Atk / 4 Def / 252 SpD
Careful Nature
- Body Slam
- Earthquake
- Curse
- Rest
Great set, I see no problem with it and you should keep it
Blastoise-Mega @ Blastoisinite
Ability: Mega Launcher
EVs: 248 HP / 252 SpA / 8 SpD
Modest Nature
- Aura Sphere
- Surf/Hydro Pump
- Ice Beam
- Dark Pulse/Dragon Pulse
I replaced Rapid Spin because none of your team is gonna suffer too much from Rocks/Spikes. Those two are just coverage, you can keep Rapid Spin if you want but I think it would be better. Water Pulse is too weak even from Mega Launcher Boost, Surf or Hydro Pump should be your STAB
Doublade @ Eviolite
Ability: No Guard
EVs: 248 HP / 252 Atk / 8 SpD
Adamant Nature
- Iron Head/Toxic
- Shadow Sneak
- Protect
- Swords Dance
Doublade is built to stay in, not exactly sweep. Swords Dance is nice and the Shadow Sneak does a lot after +2.
Shadow Claw does not have priority, being swept away by Infernape, Entei, Nidoking etc before it has a chance to use it
Hydreigon @ Choice Scarf
EVs: 252 SpA/ 4 SpD / 252 Spe
Timid Nature
Ability: Levitate
- Draco Meteor
- Dark Pulse
- Focus Blast
- Fire Blast
Come on? Why would you run Hydregion with a Choice Scarf with no Dark Pulse? It's good STAB and chance to flinch, U-Turn was useless as it would normally be locked into Drac or DarkPulse, It wastes a slot for a good move.
Cresselia (F) @ Colbur Berry
Ability: Levitate
EVs: 252 HP / 156 Def / 68 SpA / 32 SpD
Bold Nature
- Psyshock
- Thunder Wave
- Moonlight
- Calm Mind
Changed investments for EVs a bit, this will take Dark Pulse and Shadow Balls better. Moonblast was just asking to be replaced, TWave has utility and cripples sweepers
Anyways, this is just my opinion, you can choose to reject. OK, have fun battling!