The team looks really good! Some things should be changed in my eyes, though. I'll bold changes and explain why.
Lopunny @ Lopunnite
Ability: Limber -> Scrappy
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Return
- Thunder Punch
- Ice Punch
- High Jump Kick
Lopunny was awesome! I changed ability because limber is just a better ability in case you don't mega immediately and they use prankster Thunder Wave. High Jump Kick > Drain Punch because you need the power and if the bunny is hit it can't really survive.
Ferrothorn @ Rocky Helmet
Ability: Iron Barbs
EVs: 248 HP / 8 Atk / 252 Def
Relaxed Nature
IVs: 0 Spe
- Leech Seed
- Stealth Rock
- Gyro Ball
- Power Whip
This is I think the first ever perfect ferrothorn set I've seen. Way to go!!! :)
Chandelure @ Choice Specs
Ability: Flash Fire
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Shadow Ball
- Flamethrower
- Energy Ball
- Hidden Power [Fighting]
Just a small item change allows for even more attacking power, which can be threatening if they don't have a method of counter.
Mandibuzz (F) @ Leftovers
Ability: Overcoat
EVs: 252 HP / 4 Atk / 252 SpD
Careful Nature
- Roost
- Knock Off
- Brave Bird
- Toxic
Another perfect Pokemon! Yay!
Magnezone @ Air Balloon
Ability: Analytic
EVs: 252 HP / 64 Def / 128 SpA / 64 SpD
Modest Nature
- Discharge
- Flash Cannon
- Signal Beam
- Tri Attack
So what's with all the changes? This will do a lot of damage when used well.
Landorus-Therian (M) @ Choice Scarf
Ability: Intimidate
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- U-turn
- Rock Slide
- Brick Break
- Earthquake
I have no words (in a good way).
This team was really great, but I think my tweaks will make it really really great. Hope I helped!