Acorn4-as folk musicians know full well, even though the melody is a line of single notes, those notes pretty clearly define the vertical harmonies. Pachelbel's basso continuo dictates the chords pretty clearly, and, though they often are stated horizontally chords are still chords--

As to the other, when you write music in the folk idiom, the ideas that you use have been used for the last 400 years, so it's pretty hard to find anything "new", and if you did, it wouldn't be "folk".