My name is Jordan Fields (changed from Fagot in the early '70s). I currrently live in Maryland but I'm originally from Chicago. I remember that a Grace Fagot was in the Chicago phone book years ago but I never knew her. My uncle, William (Wolf) Fagot, who was not your great-grandfather, told me that Grace was some kind of a cousin by marriage but he wasn't very specific about that and I never asked him for details. He's been gone for a number of years, though he lived into his 90s. He was my father, Saul's, older brother. I can't see how we could possibly be related to the French Fagots, who very likely are Catholic.
Oddly enough, I once knew a Bob Trilling. He and I were fraternity brothers. Unless you are younger than I imagine you are, he can't be your grandfather. The one I knew would be or would have been an attorney in the Chicago area and was married to and divorced from a woman whose first name was Sandie.
Have I hit anything that makes a connection for you.