I called Lufthansa-they confirmed that any change before departure would trigger rebooking fees. They can only accommodate me in case of a misconnect.
Am I right in thinking that on arrival in MUC, from FRA, I will NOT need to go through security again, just passport control? I am referring to the standard security check, not the document check/secondary search they conduct for US-bound departures.
And no, I am not eligible for automated border control in the EU. I travel on an Egyptian passport.