Was not Kennedy president when the gulf of Tonkin caper was hatched up
I don't know about when hatched up. He was not when it "happened".
Not likely, the Gulf of Tonkin was nearly a year after Kennedy's assassination. The US had been informally involved in Vietnam since the late 50's - supporting the South Vietnam leader who refused to hold elections!
However, it is reported that Kennedy sanctioned (but not confirmed, obviously) the assassination of that leader. And It was Kennedy who sent military advisors to Vietnam, to support South Vietnam.
"May 1961: President
John F. Kennedy sends helicopters and 400 Green Berets to South Vietnam and authorizes secret operations against the Viet Cong"
https://www.history.com/topics/vietnam-war/vietnam-war-timeline
So it is probably accurate to suggest that Kennedy started to increase military presence and participation in the war with Vietnam, but Johnson substantially increased that presence and participation.
"William Westmoreland
By this time,
U.S. forces were already engaged in bombing campaigns on the border of Vietnam and Laos (with the intention of disrupting supply transport to North Vietnamese troops) and supporting the South Vietnamese in raids of Viet Cong strongholds in rural areas of the country.
In the summer of 1964, with U.S. naval support, the South Vietnamese began a coordinated series of commando raids along the North Vietnamese coast. In July, at the advice of Lieutenant General William Westmoreland, commander of the U.S. Military Assistance Command, the focus of these attacks shifted from commando raids on land to
shoreline bombardments using mortars and rockets. (History conveniently omits where these mortars and rockets were fired from. But clearly the US were already engaged in dropping bombs on Laos and Vietnam. My addition and edit.)
These actions on the shores of the Gulf of Tonkin were conducted with U.S. naval destroyers stationed nearby—hence, the presence of Maddox and Turner Joy, which were also there on recognizance and intelligence-gathering missions."
https://www.history.com/topics/vietnam-war/gulf-of-tonkin-resolution-1
So the Gulf of Tonkin may have been, some might argue was inevitably, an intentionally created or non-event designed to gain support for increased US military presence in Vietnam.
Now the Bay of Pigs.......