Will This Pokemon Set I Have Will Help To Defeat The Battle Frontier , In Pokemon Emerald Verion?

This are the Pokemon i have , 1) Breloom – sky uppercut (level 60)
Solar beam
Giga Drain
Brick Break
2) Gardevoir – Shock wave, Shadow ball, thunderbolt, phychic (level 60)
3)Altaria – (level 50) , Dragonclaw, dragon dance, dragonbreath, Ice beam.
4)Flygon – (Level 50), Dragonclaw, dragonbreath, flamethrower, crunch
5) Absol -(Level 60 ) , Thunderbolt , Ice beam, Flame thrower , Iron tail.
6) Swellow – (level 60 ) , Fly , Facade , Aerial Ace , Steel Wing.
7) Sampert – (level 60 ) , Hydro pump , surf, ice beam ,
earthquake.
Ninetails – (level 60) , will – o -wisp , confuse ray , overheat , flamethrower.
so , could someone help what is the one more pokemon i should add in my level 50 team , and what are the three level 60 pokemon i should for choose from my pokemon set for the battle frontier?
if i need to add any pokemon pls say and any move i should add pls say! And which is better to choose in battle frontier, Level 50 or open level?