I've done some research on John Hugh McDowell. My g-grandfather's family bio is in his book, The McDowells and Their Connections, but we can't find any connection between the two of them or figure out how John Hugh knew him to include his story. His story is in a section of the book of McDowells without any connection to the other McDowell lines that are in the book.
My e-mail is still firstname.lastname@example.org
if you want to "talk" more.