mickey, have a scout around on Ebay or Amazon for this book
"Big Beat Heat : Alan Freed and The Early Years of Rock and Roll" by John Jackson
US Schirmer Books, 2000
[ISBN no. 0-02-871156-4 paperback]
[ISBN no. 0-02-871155-6 hardback]
It's a very thorough (400 pages) and readable overview of the record business in fifties New York - it'll help you make sense of the connections.
No mention of Barbie Gaye, Darl, Johnny Roberts so you've dug into previously
undocumented areas.
I found a copy about ten years ago for a pound in the excellent Fopp Records in Glasgow
but I've no idea how much it goes for these days.
There was an NBC TV movie based on the book which I haven't seen .. it might be
available on DVD.