I don't know what to say. It seems like everything is there, but nothing is...
Мугайс, vampires for the Necromancer will be called ghouls (look at the vampires from 3, IMHO they don't pass for full-fledged bloodsuckers), two varieties – I've simply exhausted my supply of gothic units, maybe you have a suggestion? Commanders – here is a clever move, actually they were conceived as energy vampires, but if anyone thinks energy beings have no place in Heroes, then they can be presented as ordinary ones. The pale youth is a stereotype for both bloodsuckers and energy vampires.