Figures are getting stronger for each post dude I'd love to know how much time you spent on them though.
here's a crit/suggestion. In your lates update, I see that you put in little accents here and there, but they do not convey the form. Unify and refine your shadow shapes more. For the sake of structure, neglect the reflected light you see in the shadow. Try to be as specific as possible with the shadow shapes and pay close attention to the edge variety. If you have a drawing made of two tones (paper value, shadow value) and you find that the form is still not described well, it probably means that there are areas that still needs to be more spesific...andding more values/shadow accents or whatever won't fix the problem.