Three Battle Frontier

[EspeonSun]

Swampert/Item???
Mud Shot
Muddy Water
Earthquake
Ice Beam

Salamence/Item???
Flamethrower
Fire Blast?
Hyper Beam?
Iron Tail?

Blaziken/Charcoal
Fire Blast?
Over heat ?
Blaze Kick?
Slash?

The question marks are the stuff i need help in. Change Attacks and items and help me out!!

[Lucavi]

Never use 2 of the same type moves

Salamence @ Choice band
Adamant nature
~ Aerial ace
~ Brick break
~ Earthquake
~ Rock slide

Swampert @ Leftovers
Relaxed / Brave nature
~ Earthquake
~ Ice beam
~ Surf
~ Curse / Rest

Blaziken @ (Whatever here, it doesn't matter much tbh)
Hasty nature
~ Fire blast
~ Rock slide
~ Sky uppercut
~ Swords dance

you can also try EndRev Blaziken with Salac berry, but it's hard to get ingame

[Ness]

Ok here is my suggestions. Since you need help with the Battle Frontier I'm not suggesting any items which you get from the Battle Frontier. I'm assuming that you already have these Pokemon so I'm not going to suggest egg moves. These are very realistic and attainable movesets. However I'm not an expert at the Battle Frontier so I can't guarantee this will work.

Swampert@Leftovers
~Rest
~Sleep Talk
~Earthquake
~Ice Beam

Sleeptalker set. Very dangerous because of its durability. When low on health Rest then use Sleep Talk

Salamence@Shell Bell
~Return
~Earthquake
~Dragon Claw
~Fire Blast

Mixed attacker. It can land a Super-Effective against a lot. Anything it can't just use Dragon Claw for STAB.

Blaziken@Lax Incense
~Overheat
~Return
~Sky Uppercut
~Attract/Aerial Ace

Meh. Blaziken is hard to work with. Overheat will be effective only twice before switching. Not much to say. Attract can be pretty helpful and probably more useful than Aerial Ace. Lax Incense to help Blaziken avoid any attacks because he can't take many.

[hsb39]

I like what you've done for an ingame team, works a lot! Although I think that AA is better on Blaziken for there are a lot of Fightings with EQ.