Right after Quinn's assault, when she talks to Riona, she says:
"And given how it worked out with her ... (she talks about Mona)
... you should drop Maya before you even attempt something. "
At this point, Quinn still thinks she can get Maya involved.
I think there are several different things about Quinn's scheming. First the restaurant, which brings in a little bit of money for the girls and Quinn, but clearly it is not enough to pay all the school fees of several students.
Besides, there would be something else with Burke involving scholarship shenanigans. When a girl is in dire need of a scholarship, Quinn has a solution with Burke. Now, it remains to be seen what it is exactly, why Burke is involved (he's just a pervert, or there's blackmail), how it works, ...
... but above all what did Quinn gain from it?
She's got a source of income, a mutually beneficial relationship with the professors, subordinates that'll listen to her as long as the order is within their job scope, and a trustworthy lackey, Riona (who's probably not gonna be as trustworthy now since she's getting closer to the MC).
I'm personally not a fan of Quinn due to the fact that she's hiding way too many dark secrets, has an incredibly aggressive personality and seems to treat the people around her as disposables. I can understand why people like her, since her character is slowly developing and she starts opening up to the MC. She's making herself vulnerable to someone when she doesn't like to have weaknesses, thus showing a softer, more loving side to the MC.
However, I just can't bring myself to like her after knowing just how much of a schemer she is, and how she doesn't take responsibility for her actions and brushes them off. I do think she might feel some hint of remorse, but it still doesn't excuse her from taking responsibility. Case in point, her being the person in charge of telling the DIKs that their deal was off.
Anyway, strayed off topic there for a bit, but I doubt the cash she rakes in is for any of the HOTs, it's probably mostly for herself. From Episode 6, we do know that she's involved with a drug cartel, and there's a mentally ill woman that lives in their site of operations. There's a possibility that the woman in question is her mother, and she's doing the work so that she can afford to send her mother to a hospital. Again, just a possibility.
As for Burke, her deal with him might've started way before we entered B&R. Without knowing the specifics, we can't infer too much, but I do agree that he's a pervert that preys on college girls in exchange for a tuition offer to help out with their financial status. We've seen in the scene with Stephen and Jade that he didn't deny having sex with 3 college girls when Jade asked him about it. She knows this isn't the first time something like this has happened, thus making me think that Stephen has no remorse for his actions though it seems like he does. Not sure if she's tried taking action, guess we'll just have to see what the future has in store for us.
Although his actions are morally questionable, I'm unsure of whether it's illegal for such an exchange to be made, thus I think I'd need someone else to shed light on this issue.