GUEST,

For the first point, my original question goes to this issue of how much do I need to change before it is a new song that I own. My comment about taking a Led Zepplin tune (or any modern pop song)and swapping a few words or changing a few notes is still going to see you with a lawsuit by the original song writer.

McPeake's family claimed the copyright, but a recording of McPeake Senior acknowledges that he had heard the song from someone else and then 'messed around' with the tune.

This is largely an academic discussion, but from what I have researched, I don't think the McPeake family have a valid claim to the copyright, because the changes to the lyrics and tune are not substantive enough to make it a 'new' piece. As stated previously, I'm not a lawyer, and just applying the 'reasonable person' test.