When your job is ready for assembly, remember to coat the screw threads with a mixture of WD-40, and { I prefer Hi-Temp Copper Anti-seize} anti-seize. This step is important for the future removal of the fender pan, to service such items as the hydro pump, and related parts.
I tried my Dremel Tool with cutting wheel, and notched out a slot, in which I thought I could get away with using a chisel and ballpeen hammer to knock the rusted screw loose. I had no success because the hardware was just too tight, and would not come loose. I simply ground the screw head away, and the stud fell through to the ground.