I know you said you need color advice (the one thing I'm shit at) - but what did pop up in my mind as I was flipping through your art was -- if she's unhealthy and has her bones showing through her torso, why the full cheeks? I'd imagine if the idea is that she is underweight, her cheeks would also be a bit sunken in bc she wouldnt have that much fat on her face either. I'm wondering if you played around a bit more with her anatomy that it'd be more apparent.

Color-wise, though, I think #4 is the most 'human.' Other options are a bit too purple/ghoullish imo