As I remember, those are phillips head type screws. Try using a Dremel tool with a cutoff wheel to cut a slot across the screw wide enough to use a good quality flat blade screw driver. Then apply heat from a propane torch to the screw head before backing it out. The heat should loosen the thread locker material enough to allow it to back out. Don't heat it too much. After the screws are out, replace them with metric socket head cap screws. Let us know how it works out.
Ken