McGeorge Bundy was at the Situation Room. Averell Harriman was at the Foggy Bottom headquarters of the State Department.
Max Holland's The Assassination Tapes, pg 57:
<quote on>
At 6:55 p.m. Johnson has a ten minute meeting with Senator J. William Fulbright and diplomat W. Averell Harriman to discuss possible foreign involvement in the assassination, especially in light of the two-and-a-half-year sojourn of Lee Harvey Oswald [in Russia]...Harriman, a U.S. ambassador to Moscow during WWII, is an experienced interpreter of Soviet machinations and offers the president the unanimous view of the U.S. government's top Kremlinologists. None of them believe the Soviets have a hand in the assassination, despite the Oswald association. </q>
The US governments "top Kremlinologists" were Llewellyn Thompson, Charles Bohlen, George Kennan and Harriman himself. There was no consultation between them that day.
There's no record of contact between Harriman and the generals.
According to Craig Roberts and Jim Bishop, it was McGeorge Bundy who claimed to have spoken to Johnson on AF1.