Since your regulator is toast anyway, my thoughts are:
carefully protect door and cut the regulator to handle shaft shaft off as short as possible
remove all regulator screws--dont forget the lower divsion bar hardware
make sure to open vent window to remove tension from division bar
bend down lower tab/bumpstop of anti-rattle felt at back of door
wiggle regulator back in towards door inside and see if the whole thing, glass and all, will drop down a little.
if that works, unscrew top scew of division bar and see if you get movement of the glass.
Goal is getting the glass down far enought to let you pull the snap clips holding the glass channel to the regulator assembly. After that it would be regular R&R procedures.
Good luck, you have a lot fighting you to try and NOT break the glass...