That being said, StD and BoC models are less expensive points-wise, as they don't have the abilities and summonability baked into their points cost like models with the Hedonite keyword do. It might be effective to run mostly mortals or beasts in the list itself alongside a keeper and epitome to use the locus and horrible fascination. Then you can summon demons as needed as you generate depravity, based on whatever it is you need at any given time.
Basically no matter what you run as your baseline you're going to at least be summoning demons, completely eschewing them is going to be a handicap.