Holdon, Cowboy...
See how much stud you have sticking out if you remove the plate? Use a liquid nut release agent like that fish oil-40 on the other nut.
Once the plate is removed, you now take a hammer and shock the stud with a few good blows and more WD. Then, buy a brand new set of tiny needle nose vise grips. You take the jaws and bite down hard on the remaining stud.
This is the money shot now... You need to both act like a torsion bar on the vice grip ~ Loading and unloading ~ Then, shock the stud as you load to lefty loose see where I'm going I need a drill bit?
Take a sip. Relax. Move slow and careful.