#1 Ricky Scaggs and I don't know who; Ebbie, very much doubt the answer is F&S #2 John Duffy and Charlie Waller #3,4 agree with Ebbie, who got there first 5,6 don't know #7 by default, the Geezinslaw Bros. (Not in Bluegrass, but Bob and Ron Copper are cousins, not brothers) #8 Joe Val, and William Bradford Keith, whose ancestors really DID come on the Mayflower #9 hadn't known this one till Mousethief reminded me #10 (guess) Doc Watson
and now my own Bluegrass trivia question, the equivalent of Who is buried in Grant's Tomb: who played mandolin on the Bluegrass Boys' recording of Muleskinner Blues??