Whimsicott
Grass-type STAB isn't particularly good, at least when compared to fairy. So Switch Giga Drain to Moonblast on whimsicott and definitely use Leftovers rather than Focus Sash.
Arcanine
I'm not sure if you understand how the Assault Vest works; it refrains you from using status moves so no Morning Sun. Therefore, switch it for Leftovers or Rocky Helmet and run 252 HP / 252 Def / 4 Attack with an Impish nature. However, if you don't want that set, then switch Leftovers or Rocky Helmet for Life Orb, and anyways use Extreme Speed over Wild Charge.
Noivern
You ought to consider Trick or Boomburst over U-Turn.
Suicune
What are your goals with the EVs? What in particular are you trying to achieve? If it's nothing, then you should use standard 252 HP / 252 Def / 4 SpD with a Bold Nature which gives you the enough physical bulk to setup; Calm Mind will make it for the lack of special investments. By the way, Scald is much better than Surf for its burn chances are very valuable, and are an excellent tradeoff of the extra pointless power Surf offers.
Snorlax
Snorlax needn't defense investment; it uses Curse to make for the lack of it. However, what your Snorlax lacks and should have is some recovery; RestoChesto is a good idea, especially that Snorlax has access to Recycle for unlimited ChestoCycling although it will restrict your coverage very severely. Don't use Double Edge, Snorlax is supposed to be a bulky mon that should abuse its fantastic staying power. Instead, use Frustration as it is a more reliable Normal-STAB but also, it blocks random Dittos from doing any signifant damage.
The other are fines. Other Remarks:
Your team has no actual walls, just setup Pokemon. Not saying that's particularly "bad", but it makes you horribly weak versus phasing, Taunt or Clear Smog Amoonguss among others, while also not having enough defensive power to stop your opponent so once they've started setting up, any powerful pokemon has the potential to sweep your team after a single boost.
You have 2 stealth rock weaknesses, and no way to defog/spin. I can see this being a huge issue for you. Whimsicott seems a tiny bit out of place, although its fighting and dragon resists are nice for your team, so maybe drop it for Tentacruel / Forretress / Crobat.. anything that can Defog or Rapid Spin while keeping most of the synergy Whimsicott had is fine. Just watch out for overlapping team weaknesses.
Hope this helped.
