I wonder what you mean by ‘no longer worked at all’, as in did you, by using a new skeleton, get basic constraint functionality to work or fix all the problems OP mentioned?
Asking because it would take so much time for me to retarget everything 
I wonder what you mean by ‘no longer worked at all’, as in did you, by using a new skeleton, get basic constraint functionality to work or fix all the problems OP mentioned?
Asking because it would take so much time for me to retarget everything