The point is not who made them (which is often unknowable and not a very interesting question) but how they were transmitted. You are saying that print never figured in the process. I am saying that it almost always did; that songs moved to and fro between oral transmission and paper. Steve Gardham has documented the process quite thoroughly - you can trace features in orally collected songs which have to have gone through a known printed version.

For tunes, Dunlay and Greenberg's book on Cape Breton fiddle music goes into the sources quite well. So does Alois Fleischmann's "Sources of Irish Traditional Music", though he's less interested in tracing through the whole process.