An interesting writeup. :-)
One comment - you write:
At JFK's death there were <15 K Murican 'advisors' in Vietnam -- and JFK was himself mightily disturbed by realizing that his inactions had directly caused the assassination of Ngo Dinh Diem (sp) [it has been said by several, later]. He planned to reduce the 15K, as of mid-Nov. '63.
I recall a USNews and World Report article from maybe 15 years ago that said that Kennedy had [link|http://www.pbs.org/wgbh/amex/presidents/nf/featured/ken/kenfp.html|signed off on the coup] (an American Experience link) - it wasn't really inaction on his part. I doubt that the US knew that he would be killed though.
I think there's evidence on both sides on whether he'd had ideas for reducing US involvement in Vietnam. From the same link:
As 1963 wore on, Kennedy considered his options. He could commit further, even send in American combat troops. He could withdraw, and let the Communists claim victory. Kennedy found neither solution palatable. Then another option developed. Some of Diem's generals began to plot a coup against their leader. Kennedy, who had promised to help developing nations help themselves, gave his approval.
On November 2, 1963, Ngo Dinh Diem died at the hands of his generals. In South Vietnam, citizens responded positively to the coup. With Diem out of the way, hopes rose that South Vietnam could stave off the Communists.
Less than two weeks after Diem's death, Kennedy himself was assassinated. The man who promised the world he would stand up to the Communists had done so--for better and for worse. Now another Cold Warrior, Lyndon Baines Johnson, would take his place. And in the jungles of Vietnam, America's bloodiest Cold War confrontation was only beginning.
[link|http://www.chuckiii.com/Reports/History_Other/The_End_of_the_Diem_Regime.shtml|Here] is an article that discusses the history with a fairly similar viewpoint. Take it with a grain of salt though - no cites are provided.
Cheers,
Scott.