I'm never really sure what people mean by slutty. To some it means 'had sex with more than 5 people in their lives', to others it's 'had sex with more than 5 people in a 2 year period, to yet others it's 'fucks whomever they want whenever they want'.
To be clear, it's my opinion that all of these are acceptable behaviour. Unless they're being unfaithful (fucking whomever you want whenever you want is still acceptable when in a relationship if it's a known and agreed aspect of the relationship and all parties – allowing for polyamory – have the same freedom) or unsafe.
Assuming the, in my experience, most common definition, that being the latter, the only girls I can think of who really seem to fit that description would be Krystal, and probably, from the way she was behaving when we met her, Krystal's mother, and, I'm guessing based on the way she's acted so far, Daphne. Darcy had never fucked anyone up to the start of the story. Skylar strikes me as the type to only fuck someone she cares about. So does Jessica (who hasn't fucked anyone yet). I get the impression the rest are similarly selective. And I don't expect Alyssa will become slutty either. What I think she will become is uninhibited and kinky as fuck. Consider the movies she had that she didn't want the MC to notice!
