Q, I was aware that that passage that I quoted didn't answer the question you asked. But, I'd been looking for a thread to post it.

Btw, I don't think that Maud Cuney-Hare's book mentions the "Oh Freedom" song. I would be surprised if this song was composed before the end of the Civil War.

Is there any evidence that "Oh Freedom"'s beginning words at least are a secular adaptation of the "Oh Canaan" or other O {Oh} spirituals?