Yeah, this all is pretty ridiculous. Looking at the tags they have on a lot of their villains, they just sort of throw every term they can at a character. :/ And, going from what little I know of LoK, I definitely wouldn’t call P'Li a “femme fatale” either.
I followed the series. For an idea of P’Li’s canonical characterization: if I say that her team are a four-temperament ensemble with her as the melancholic, that gives at least something of an idea. While I think “arc villain’s love interest” might have played into why she was on that index, I really do suspect that it was mainly on account of her character design.