Tinfoil theory time.
As the post linked by Jillybeanenjoyer states I am firmly in the camp of Thirsty Ghoul = Nikita = Yoga Girl. But the question is why was the Thirsty Ghoul introduced in ep 9 and why has this very attractive background character of Yoga Girl suddenly appeared in two different locations in ep 10.
I think DPC saw the explosion of new theories during the long wait between eps 8 and 9 and one I think that caught his eye is the undercover cop Lily theory. Unfortunately the undercover cop Lily theory has more holes in it than Quinn's arm so he couldn't make that theory canon. However that did lead him to wonder about the possibility of introducing a new character who could be an undercover cop.
Obviously we know nothing about Thirsty Ghoul/Nikita/Yoga Girl so there's not much to go on, however I do think it's strange that Thirsty Ghoul only talks to MC if he's single yet doesn't make any sort of move on him, almost like she's scoping him out. If she just thinks he's hot and she knows he's single why wouldn't she actually make a move or at least offer to exchange numbers? It makes no sense to me, and Thirsty Ghoul obviously knows MC is single because she only talks to MC if he's single.
It would make sense however for an undercover cop to be scoping out students who potentially know about Quinn's drugs and prostitution restaurant, it would make sense for an undercover cop to only be looking for single guys to scope out, it's unlikely a guy with a girlfriend in college will be using prostitutes in the same college, it would also make sense for an undercover cop to try and get to know things about a potential informant so the conversation in Derek's bar and sudden appearance in two seperate places in ep 10 would make sense for that reason too.
