Oh, I know who most of them were. Got a couple of Powder River Jack Lee stories, in fact. Have to look that up. It's a Gail Gardner story, by the way.
In the WLS book, I know at least a little bit about just about everyone there.
Recordings are reasonably easy to find for many, but not all of these old recording stars. I'll get back to you with a less than comprehensive list of what is available, though someone like Stewie (and there are others as well) probably has the info better organized than I do.