FOG:

There is no need to be talking of drilling the bolt shanks after the heads have been ground off. If it is not obvious, once the heads are removed the CV joint & axle can be removed. That will expose the bolt shanks which are about 1" long, and they can then be removed w/ vise grips. A couple of fresh ball-end cylindrical carbide burrs of 1/2" diameter will get it done. Over-thinking is an impediment.

See above post.