I tried Fagan, Faygan, Fagann, Faganne, Fegan, Feygan, Fahgan, Faghan, Faganh and several others before giving up. I think Fagan should be acceptable based on how lenient other name spellings are.
At first for the bargain with the devil I was trying to figure out how to find an F in Charlie Daniels' "The Devil Went Down to Georgia". Fiddler Johnny was the only thing I could think of. I got the right answer eventually.
His real name was never given on the show, something that was made jokes of a few times.