I think Kasumi, Kokoro, Honoka, Hitomi, Leifang and Mila are pure, Phase 4 is broken(mentally), and Christie, Helena, Marie Rose, Lisa, Nyo, Ayane, Nico, and Tina are impure
Oh I mean as far as innocence, Marie Rose never seemed to be as innocent as she looks xD she's kinda like Lili in how she looks angelic at first glance but her personality shows different like when she tells you die xD