Here goes.....
Blaziken _ Ability: Blaze
@Leftovers
Flamethrower
Rock Slide
Bulk Up
Sky Uppercut
Grumpig _ Ability: Thick Fat
@Lum Berry
Psychic
Calm Mind
Confuse Ray
HP (dark)
Aggron _ Ability: Rock Head
@Focus Band
Earthquake
Double-Edge
Roar
HP (rock)
Cradily _ Suction Cups
@Brightpowder
Recover
Rock Slide
Giga Drain
Sludge Bomb
Lanturn _ Ability: Volt Absorb
@Leftovers
Surf
Thunderbolt
Confuse Ray
Thunder Wave
Flygon _ Ability: Levitate
@Scope Lens
Earthquake
Fire Blast
Screech
Dragon Claw
Overall, not a bad a team. I've made a few adjustments. Natures don't really matter that much, just use whatever benefits the Pokemon.
Take heed that you have a x3 ground weakness, one of which is quadruple damage received.
Btw, what does rngt stand for???