Bryant, you asked about whether the old-time players-- and you mentioned several names--play(ed) with fingerpicks or their own nails. The answer is "generally their own nails."
I'm a relative newbie to clawhammer banjo--a little less than two years. It took me about eight months to get the basic frailing stroke down right. Then within a couple of months thereafter I was able to sing over a rhythmic pattern, and play banjo breaks between verses on a number of the songs. I learned double-thumbing and drop-thumbing, the techniques that are usually thought to distinguish clawhammer from frailing, right along with the early lessons.
Today I'm self-directing (no more lessons), and almost everything I play I've worked out myself from hearing or remembering or imagining a tune; don't use tab to speak of at all.
I should say that I much prefer playing with my own fingernail (middle), but it keeps breaking, so I have to use a pick a good deal of the time.
Oh, and you mentioned, among others, Bascomb Lamar Lunsford. He didn't frail; he used a two-finger up-picking style.

Dave Oesterreich