Hi! I'm gau222.
I think having Protect on all of your Pokémon is not good. Protect is only used for Black Sludge and Leftovers recovery. Sometimes it is used for Wish recovery and Speed Boost too. Other than that, it has no use(It can also be used with Pressure to stall out PP or for Mega Evolutionary purposes).
Metagross is fine, but again, remove Protect and replace it with a good coverage move since you already have dual-STABs. Try Hammer Arm. Why do you have Brave Nature. Go with Adamant Nature. With Brave, you have a chance to be outsped and KOed before you can use Explosion.
The EVs are incomplete so add 4 to Speed. Also, are you really getting a shiny? :P
Don't change this Machamp. But I would give it an Assault Vest and remove Protect for a coverage move.
I realised you ripped this set off Smogon so keep it that way, but remove Protect for HP Flying.
Your Mamoswine's item should be Life Orb, Ability should be Thick Fat since you have no way of setting up hail. Remove Protect for Superpower or S.Rocks.
This is a good Mega-Gengar. You nailed this one.
Thunder Wave and Taunt are fine but seriously, Thundurus without dual-STABs. Go for TBolt and Air Slash.
Hope I helped,
gau222 :) .