I would suggest to add some blue to the black, in my opinion. Leila looks pillow shaded (unless you zoom in), so try to give it more texture like you did with Adrian. The white you're using with Noname, needs a bit more light, unlike the white with Koli looks excellent.
The hair with Tyryss, needs to be softer in shading, use lighter colors to even it out. (Though, don't trust me on this, I'm no good with hair myself.)
Outlines are only a reference, you'll have to shade over them, eventually. Don't keep them around, shade over them according to your light source.