Perlman would be delighted to read that someone thinks of him as a Klezmer. He is, of course, the most famous violinist in the world and is, entirely, classically trained. He did, however, appear on a television show called "In The Fiddler's House" where he played with some of the great Klezmer fiddlers and aqitted himself quite well.
Joe Heany's singing style (shanos) is not for every ear. It is a cross between Mabel Mercer and Leonard Cohen with lots of echo. His primary audience was a blend of elderly Celtophiles and aspiring folklorists, I am in the first group, Ms Null and Mr. Broudy, the second. Leslie Berman claims to have dated Joe, but I think she was just bragging.
Sara Cleveland lived at Kenny Godstein's house, in Mount Airy, while he was taping her voice and tapping her brain. She was a delightful woman who knew every verse of every song from every mountain and she sang every word of every one. For all I know, Kenny made his students copy all those songs, learn them and spit back the words on a final exam. That would explain Lisa Null's evaluation of Sara's singing.

                        Mike