Until shown otherwise, Quinn and Burke are the baddies, and I'm not sure about who is worse tbh, Quinn for pushing girls into prostitution and drugs, or Burke for knowing about it, allowing it and even enjoying their services; although it's Burke probably since he's the figure with the most authority in this scenario.
DPC might introduce some kind of drug lord later, who has some kind of leverage over Quinn to make her "less bad", but if you look at the situation objectively, despite any feelings you might have for her, what she's doing does not help in anything except endanger herself and anyone even remotely related to her.
Regarding Vinny I agree with you, knowing DPC he's probably going to be a main antagonist, directly related to the bad shit that happens to the DIKs, but I'll be surprised if he's used as a scapegoat for most of the shady stuff that's going on at B&R.