As far as recording just a single verse of a song, to get the tune...the
person who did that often was Peter Kennedy, and one of the people in
Lomax's organization (Matthew, was it you?) told me he did that because
tape, at that time, was very expensive, and he was working on a very
limited budget. That's why you'll hear the multi-artist compiled
versions of ballads, each singing a single verse, on many of the "Folk
Songs of Britain" albums.