I think I would personally like the last best (standing on its own) if her face was lighter. It is nicely lit in the first and I would wish for the same in that last one.
The fact that her skoliosis is so obvious seems to give away too much about her (in my mind) ... which is why I am not so fond of the second. It's as if we are entrusted with a medical detail that is not for all to know (just feelings on my side, personal ones, no critique, never get me wrong here, please!)