I've been tossing ideas in my head on how to continue Ria's story, and I think I might have come up with something.
Heather is not actually dead. She faked her death, by wearing a bullet proof vest and a "blood packet" when Maria shot her. She wanted the world to think she was actually dead.
She wanted out of the cult too, but knew that running away with Ria at that time was a bad idea. So she faked her death to save herself, and fight the ones who hurt Ria and herself at a later date.
Maria "Sororcula" Townsend (Sister in the cabal, Ordo Invicta)
Dorothy "Dot-Com" Comstock (Hacker)