In the Banjo Newsletter article Wade was kind of saying that a lot of people claim that they were playing Bluegrass before Monroe with Earl & Lester. He was saying something to effect of he doesn't really know, he was just playing music. He also mentioned that he played three finger for awhile but went back to two.
I'll get you a copy of the article when I see you next. There's also a really good interview with Steve Martin. Man, you talk a Banjo nerd!!! He seems to love the instrument.
I don't know about it having to be three finger to be Bluegrass, I've heard some awfully good Reno & Smiley stuff that I would consider Bluegrass.