Looks like you need to just get the caliper off first. Do you have access to a welder?
Times like this, I will pop a larger nut over the head (making sure there is still room to get a socket over this larger nut) , and with the welder on the highest amps, plug weld the new nut to the head of the bolt. Start slow to make sure you have a good weld to the bolt head, then keep plugging inside the nut. The extra weld is not adding strength, so much as putting a crap-load of heat into the bolt.
Once finished welding, wait till it at least stops glowing red, put a socket on it and try wrenching it off. Worse that happens, is you shear off the nut and have to do it again.
I have never NOT had this technique work for me - it is a sure fix, but obviously you will need a new fastener. It works great on studs sheared off in manifolds (so long as you have 1/8" or more of stud proud of the surface) and especially those sh1tty studs ford put in the manifold studs on the modular motors that shear off for fun...
If you don't have a welder, then try to Centre-punch the head of the bolt, and drill in there just deep enough with a 3/16" drill bit, then a 1/2" bit just deep enough to pop the head off but leave the shank intact. With the thin rotors, and a bit of levering, you should be able to pop the caliper off the shank.
Now beat the remaining shank up, down, left, right, right on the head, and every angle in between. You now should be able to use the Irwin easy-out on the shank, and with enough beating, it'll probably just unscrew clean off... If you have it available, also try some MAPP gas on the bolt shank.
When all else fails, then by all means try to drill it out, but most of the time folks end up managing to tap out most of the good threads, leaving a compromised fastened joint. Always try everything possible to get the fastener to wind out, before resoirting to drilling.
