Why would they need to be redrilled? If they are seized to the point where snapping them is the only answer, then keep turning on them. Yes it will take a bit of force, but eventually they will break. Try to get a cheater on the handle, and bottom out the backup wrench on something solid (ground or bottom of the car). Then run to the hardware store and pick up some new bolts.
Or let them soak in PB for an hour or so. And then if you can get them to turn at all, work the nut back and forth. So loosen a turn or so, and then tighten it back on the same amount. Keep repeating this, slowly gaining on it. SOmetimes that works, but not always.