[DireAussie]

For heroes you could have:

The Weaver (can teleport anywhere, powerful in astral)
Construct Council (immobile, strong in construction, can summon mechanical men allies)
Silas Fennec (ultra stealthy, if there's a way to make a unit create unrest at a much bigger rate than normal then use it, otherwise perhaps make him a priest and special ability that removes enemy dominion really quickly).

I'm sure there's at least one from Iron Council you could use too (which I've bought but havent read yet!).