I take a dremel with a 3/4" cut off wheel and cut a slot in the bolt for a flat head screw driver on some bolts or use a good cobalt reverse drill bit. Be sure to center it and drill all the way thru to oil it from the back if it doesn't start turning.
Spray oil is your friend Id start spraying now then step up a size on the rev bit the next one may grab and turn. Then if all that fails use an easy out or drill it and re-tap or drill bigger and helicoil. hth
If I am the least bit afraid of breaking a bit or easy out I simply drill and tap then you aren't sol.