The title "Lady Margaret" in the DT for the Newfoundland song should have "Sweet William's Ghost" or Child # 77 (Group D) appended. "Fair Margaret and Sweet William" or "Lady Margaret" is Child # 74. (a version in the DT as "Lady Margaret 2")
A slightly different version of the Newfoundland text, sung by Mrs Emma Boone of Conception Bay in 1929, is included in Bronson's "The Singing Tradition of Child's Popular Ballads." There are 15 verses (13 in the DT).
Child # 77 apparently was not found in the Ozark region by Randolph or by Cox in the Virginia area. I haven't seen Brown's collection from North Carolina. So far, the NFLD verse seems unique.