> it's interesting that there still seem to be quite a few loose ends.

Seriously, folks...is there a definition of "poetry" that definitively covers all the alleged examples of a poem to the exclusion of all non-poetry? And that everyone will agree on?

I don't think so.

Regardless of your definition of "folksong," you'll find a song to fit it and others that don't.

The best way out of the definition trap, as far as I can see, is to ignore the entire folk/non-folk dichotomy entirely and just discuss the song.