I don't know if that girl is actually Lana, but the theory makes sense. Jill's mother says that she and her husband made Lana leave the house because "she wasn't been herself tonight". Maybe she was high. If Rox and Buddy are the main drug dealers of the area, makes sense that Lane got drugs from them, or even were selling for them. A rich girl like Lana would probably end up in rehab payed by her family before it's too late for her, but maybe Lana's parents didn't know how hooked she actually was. Jill wants to make a campaign to "raise awareness". Probably she thinks that, whatever it was Lana's problem, her parents weren't aware enough and doesn't want that the same thing happens with other people. Also, Lana's problems are shameful for her family, since they don't want that Jill makes that campaign. Having a junkie daughter would be shameful for a family like the Royces. And it would be a link between Jill's subplot and Quinn's&Buddy subplot. Makes sense, it's not a crazy theory.