Would you consider placement? Considering that the organs were placed between/around the legs, it's possible that Jack had already positioned her legs and feet (as they were found), and was cutting/denuding what was accessible to him from standing on that side of the bed. Maybe denuding below the knee would have meant lifting or shifting her leg. (Of the opinion he cut her legs last.)
Another thought. Are the abrasions on the back of her hand similar to the marks found on the other women's hands?
there,s nothing new, only the unexplored