I previously broke a 1/4 inch (6mm) hex bit trying to remove the oil cooler block off plugs. This time I heated up the area with a heat gun before attempting removal. I used the highest heat setting for 60 seconds, knowing that red loctite releases at ~500*F and magnesium self-ignites at ~850*F. After heating the area and waiting, the plugs turned right out.
Despite ZERO references in the maintenance manual, it appears my engine was assembled using red loctite throughout.