Chuuko demo Koi ga Shitai, chapter 0 out.
Would you used goods?
If you're gonna do that, then just make her just as sexually interested as the male lead but drop the slut angle. It saves pages of misunderstandings and doesn't come off as complete otaku pandering, since the purity isn't the big reveal.
Hairpins. She's probably the safest to make into a slut because she looks forward, but not too aggressive.
It'd be too obvious to make the gyaru a slut, same with the bookorm and the green-eyed breasts because that's be "subversive" and the obvious route to take to force the "don't judge a book by its cover" message.