Ive been really busy with school, but I'll try to get around to this, but my first thoughts are:
1) Overall very nice team, it definitely shows you have experience in the format. I always love discussing with people who play VGC.
2) What are the EV spreads made for?
3) Snorlax is in an awkward spot with this team. Without the belly drum set, he is not very optimal. I am aware the curse set has some usage, but I just feel like he wouldn't be pulling his weight (which is a lot lol) with the current set he has. I would recommend changing sets, or as I would prefer, remove him all together.
4) Your Pokemon all get caught in a very poor position when going against teams with their own elements. Yes your team has modes of speed control in Tailwind and Trick Room, but your team is neither fast or slow enough to truly take advantage of this. Building off this, if you face a team which is a dedicated Trick Room or Tailwind, you will almost guarantee lose because those Pokemon can really exploit their elements more.
If you look at some of the most popular VGC players, mixed TR and fast teams aren't the most common, but have some usage. But those teams almost always have very clear cut fast and slow pokes, meant to optimize whichever move the trainer should choose. They usually aren't middling speed Pokemon who unfortunately get caught in the middle.
5) Your last and biggest problem (imo) is lack of parity on the team. If I'm playing you, I'm always trying to predict what moves you'll do and how I can best counter that. And with this team, your using all the moves that the opponent would expect. I think this is the root of you bringing a good team to a battle, and coming out with a loss. It really throws a wrench in my gameplan when the Tapu Fini pops out a Grass knot and destroys my Mega-Blastoise when I thought I was safe. Obviously this is just one example, but I don't think the creativity can be emphasized enough in VGC. By no means don't be like those low level battlers who bring stupid stuff to games, but throw your own twist on the team!
I brought a Mega-Pinsir Japan sand team to my regionals and walked away with 2nd place. A lot of people pack HP Ice ready for the Mega-Salamence that comes with Japan Sand. Pinsir's higher attack, access to Feint, and alternative typing while still doing the whole Aerilate thing is what almost won me the tournament. Had I brought the standard mixed Mence, I have little doubt I would have been eliminated early.
Also if you want ideas, check out the most recent team I posted. I'm very proud of it, and it has definitely been one of the more successful teams I've ever built. It draws a lot of its strength from originality, and I hope it could inspire you some with the direction you want to go with this team.
If you're still interested, comment here what kind of direction you want to go with, (Trick Room, Weather, Tailwind, Mixed etc) or even just start from scratch. Tell me which pokes you'd like to keep/use, and I'll try to help you build a team from there! Again lmk if you're interested.