Cram's synopsis of Epstein's Legend is accurate, imho.
To my knowledge, any information Epstein may have gotten about Oswald from the CIA would have been gotten from Angleton, not Bagley or Miler.
Fwiw, I'm coming to believe that false-defector Nosenko told CIA and FBI what they really, really, really wanted to hear (that Oswald hadn't been recruited by the KGB) as an "icebreaker" which, whether true or not, would lead to his being accepted as a true-defector that much quicker, and which would make his "debunking" of true-defector Golitsyn that much easier.
Unfortunately, it worked.
-- MWT 
Interesting
I don’t think Helms was very impressed. And Olson felt the need to spike Bagely’s career, with this:
https://www.archives.gov/files/research/jfk/releases/docid-32359254.pdf TOP SECRET
13 October 1970
MEMORANDUM FOR THE RECORD
Subject: BAGELY, Tennant, Harrington
#386 38
1) On Wednesday, 7 October 1970 I briefed Colonel L. K. White, Executive Director-Controller on certain reservations I have concerning the proposed promotion of subject to a supergrade position.
2) I was very careful to explain to Colonel White at the outset that my reservations had nothing whatsoever to do with Bagely's security status. I explained that it was my conviction that Bagely was almost exclusively responsible for the manner in which the Nosenko case had been handled by our SR division. I said I considered that Bagely lacked objectivity and that he had displayed extremely poor judgment over a two year period in the handling of this case. Specifically as one example of Bagely's extreme prejudice I pointed out that the SR division had neglected to follow up several leads provided by Nosenko which subsequently had been followed up by this office (Bruce Solie) and that this lead us to individuals who have confessed their recruitment and use by the Soviets over an extensive period of time.
3) I explained further that Bagely displayed extremely poor judgment in the actions he took during that time that Nosenko was incarcerated at ISOLATION. On many occasions, as the individual responsible for Nosenko's care, I refuse to condone Bagely's instructions to my people who are guarding him. In one instance Bagely insisted that Nosenko's food ration be reduced to black bread and water three times daily. After I had briefed Colonel White, he indicated that he would refresh the Director's memory on Bagely's role in the Nosenko case at the time he reviews supergrade promotions.
Howard J. Osborn
Director of Security
