I suppose one possible answer to the question "Where's Fennario/Fernario?" it could be that the name is a misremembering (or "folk processing") of "Killarney O" in the original. Not many Appalachian folks in the late 19th century would have been familar with "Killarney."

It would be interesting to compare the earliest "Fennario" versions
with the "Killarney" versions tosee just how similar they are. That might clinch the matter.