Thanks for the analysis, Nerd. I've dipped into folklore in my scholarship when comparing literature with Ethnographic materials, and came to the same conclusion regarding "myth" vs "myth" and the rest. It makes perfect sense to apply what amounts to the science of folklore to folk-music-lore.

For clarification or illustration purposes, one might look at the line from opera to operetta to musical theater. All are legitmate musical entertainment, but there are degrees of difference in training, performance, song vs spoken word, etc. We (I hope) understand that Fidelio and Oklahoma are entirely different creatures even while both accomplish storytelling tasks.

SRS