Tough one. I would still consider the blue wrench, but only to heat the lug nuts enough to get them to release. It sounds like the studs on the adapter are turning with enough resistance that a hot lug nut may spin off.
Otherwise, lots of patience and a long drill bit. Center punch the cap of the nut and start drilling....all the way into the stud to weaken it.
What ever you do, don't pull the shotgun out, nor the angle grinder
