You give your Garchomp an offensive set but defensive item? Dual Chop and Poison Jab are useless on Garchomp. Fire Fang to an extent. Replace the set with Stealth Rock, Fire Blast, Earthquake and Outrage/Dragon Claw/Stone Edge. If you keep your current EVs replace Rocky Helmet with Focus Sash and send Garchomp out first as a SR Suicide Lead (at your discretion).
As Sumwun said, two Megas isn't a good idea, especially with Amp and Lopunny, as their non-mega forms are very weak. In fact, I'd suggest getting rid of both and making Metagross your new Mega. I'd recommend the following set:
Metagross-Mega @ Metagrossite
Ability: Tough Claws
EVs: 32 HP / 252 Atk / 220 Def / 4 SpD
Impish Nature
- Iron Head
- Zen Headbutt / Ice Punch
- Earthquake
- Hammer Arm / Bullet Punch / Ice Punch
This new set turns Meta into a beast that can absorb physical hits and give twice as much. It will somewhat help you deal with the myriad of brute force junkies like Mega Pinsir and Scizor which would ruin you otherwise.
Your other four members really aren't cut out for OU or AG to be honest. I'd personally scrap the team and work on a good base like MegaMeta and Garchomp. Right now, pretty much every attacker (including but not limited to Talonflame, (Mega)Scizor, (Mega)Heracross, Tyranitar, Serpiror, Rotom-Wash, Mega Medicham, Lati@s) and walled by Mew, Celebi, Salabye, Slowbro...
Basically a lot of powerful and prominent Pokemon ruin elements of your team. You should learn threats to your team and adjust as necessary. Think about things like 'do I have anything to counter fast sweepers?' and 'can I do enough damage to break through these walls?'.
We can fix sets and recommend tactics but we won't rebuild entire teams, we expect you to have a decent knowledge of battling. If there's anything you don't understand just ask.
