I meant to post the answers before I left for Grass Valley but in all the excitement I forgot! Here they are:

1. “Fiddlin” Art Wooten was the fiddler who recorded and toured with all three bands. He was a Blue Grass Boy at the time Bill Monroe first joined the Opry in 1939. He left in 1940 but returned shortly after and appeared on Bill's second session in 1941 where he was featured on “Orange Blossom Special” and “Back Up and Push”. In 1949 he played with Flatt & Scruggs and recorded four songs with them including “Why Don't You Tell Me So”. He also played with the Stanleys in 1949, then returned with them in 1952 and recorded one session with them.

2. The Dillards recorded Dylan's “Walkin' Down The Line” for their album 'Live! Almost!”, released in 1964. Bassist Mitch Jayne introduces the song with his description of “Bobby Dylan” who has a voice “very much like a dog with its leg caught in barbed wire”.

3. Barbara Mandrell appeared on “Bill Monroe and Friends”, the 1984 album of duets pairing Monroe with various country artists. She sang and also played dobro on “My Rose of Old Kentucky”. The next year Mike Auldridge sang and played dobro on “Remember the Cross”, along with other members of the Seldom Scene, for the “Bill Monroe and Stars of the Bluegrass Hall of Fame” album.