Reading through this, I've wondered about the possibility before myself. Pretty much everybody on the forum knows Dulles, Cabbell, Bissell and Walker were forcibly retired not too long before, by JFK. All still useful in some respects with lots of contacts.
But, it seems like there was at least one more relevant upper-level CIA person who retired less than a year before the assassination. I can't remember the name or position, first thought Barnes, no. You say Lansdale, Edwards, etc. Any idea who I might be thinking about? Anyone else?