Welcome to Beatlelinks, LadyBug!
We hope that you will enjoy the show.
As far as your question goes, I can't give you a complete answer because all my Beatlebooks are packed for my impending move. The best I can come up with off the top of my head is that during the late 50's and early 60's, it was common for a band name to emphasize a lead singer. When George Martin auditioned the Beatles, he considered each of them for the lead role before dropping that idea. Don't know where the "Moondog" bit came from, though; maybe that's just something John came up with.
Contributing Editor for Rooftop Sessions
--A science fiction series about John's descendants--Updated 5/16/02