First picture is meant to address the proportion critiques: i think i have the skull proportions correct. I honestly can't really see any deformation or irregularities.
The hair dithering is how i'm able to do the several shades of hair without adding further colors, can't get that look without doing it. I don't think it's very noticeable, at least not on my screen at 1x.
The second and third images refer to Khris' comment. That pose is close, but mine is not as tilted up, eye level is at ours, with a slight chin tilt upwards. More upper lip is visible from your reference at that angle, and the model has bigger lips. I was going for smaller tight lips, while still young girlish ones.
As for the green for the highlight, i think it reduces the whole contrast, and changes the lightsource completely, losing the harsh pale lighting tone i wanted. As for the second tone, i tried some warmer colors but it needs to be at a somewhat inbetween color between the brightest highlight and the next warmer color, otherwise it doesn't look as good, as whole. So it's at a yellow-peach.