Burning Legion, what units would they use?

Okay, I'm making a campaign involving the Forsaken, the Burning Legion, the orcs on Draenor, and the Blood Elves. I need to know what units they would use to fullfill each role. And I know there are several new demons on WoW and I'd like to see pictures of them, mainly the Imp, though, because I was going to make an imp before WoW.

Low Tier:
Felguard (expensive melee)
Imp (cheap ranged, hurls fireballs) (upgrade - splash damage)
Infernal Contraption: (Cheap Siege) (upgrade (like troll berserkers) - Infernal Juggernaught)

Mid Tier:
Felhound (anticaster) (upgrade - magic immunity)
Eredar Diabolist (offensive caster)
Maiden of Pain (disruptive caster)
Void Flyer (light aerial Voidwalker) (upgrade - phase shift)

High Tier:
Overlord (uber melee) (upgrade - Life Steal)
Queen of Suffering (ranged/caster) (upgrade - Life Drain)
Nether Dragon (heavy aerial unit)
Doom Guard: (Very expensive hero-class unit)

Hero:
Pitlord (mannoroth + hero glow)
Nathrezim Councilmember (elite dreadlord)
Eredar General (archimonde)
Void Binder (hero voidwalker)