I just ordered a book today that has actual musical scores from Lorca's plays. WTF! I did not know about this until today. Of course, I should be the expert in this stuff by now, but no.
People remembered the music wrote and wrote it down. They aren't written down by Lorca himself.
Now I realize what Germaine Montero is singing is Lorca's own music. So this explains somewhat why Lorca became such a musical figure. It's not just the poems, but the plays. Specifically, the song from the plays. Lorca meant these songs to be sung, and composed (or adapted) the music for them.
So now, there are two factors I had known about but underestimated by a country mile: Lorca as composer / Lorca as playwright. Now a lot of things are making more sense. My original orientation was toward music other people wrote, and toward settings of the lyric poems more than the plays.
This does not change anything I've already written, it just makes the book more rounded and complete.