Yes, it’s complicated with those limitations. The only cheap unit you allow is ghouls, so it’s hard to get enough drops. It will be an elite army.
I think the undead dragon is to expensive for this list. And never like the werewolves regiments. I have been playing a little and came out with 2 list:
The first is more alpha strikey. Both Werewolves hordes and Soulreaver cavalry should go usually together with Ilona. Then both Soulreaver infantry behind the Ghouls and supported by the Vampire Lord. Two unit groups are very few for 2000 pts. Maybe you can move Ilona and Soulreaver Cav or one Werewolves horde away from the other two units, but losing inspiring. Or advancing a little slower and trying to give them inspiring with the Vampire Lord for the first turn (while giving it to the infantry too).
The second one have an alpha strike group formed by the Soulreaver cav, the Werevolves horde and Ilona. Then the Soulreaver infantry again behind Ghouls troops. Finally the Ghouls horde which could be buffed by the Standard Bearer’s Bane Chant, hitting very hard, and supported and protected a little if neccesary by the last two Ghouls troops.
I think if you want a vampire army, you need to use Ilona’s formation. It’s just to good now.