Well Eddy, I believe you have heard this from me before on another thread, but I don't post it frequently because I don't want to sound like a broken record ( it's funny how out-of-date that idiom is), but here is my take on that.
My working theory is that the assassination was set-up to be a pre-text for a Cuban invasion, but that invasion plan was undermined by a far-right industrial faction.
It is often said that the invasion was aborted for fear of WW3; I am not buying that because that possibility would have been present prior to the planning of, and the act of assassination. So that problem didn't pop-up after the DP hit.
I am thinking that Texas industrialists and right-wingers double-crossed an Anti-Castro / Mafia element, (who actually did the shooting), by eliminating the evidence of conspiracy, and mixed that with a little bit of blackmail. They foiled the conspiracy angle. They did this, hypothetically, by making evidence disappear and making other evidence appear. I suspect a shooter or operative was killed in the Plaza, who was supposed to be ID'd as a Pro-Castro Cuban. They made this body, or person, and other evidence, disappear.
They, The Texas industrial and right wing faction, were able to do this because their original responsibility was passive; they were supposed to do nothing, therefore there would be no evidence implicating them locally. Perhaps they were supposed to create a lot of noise, static and background noise so the hit would not come as much of a surprise as well as causing resources to be stretched thin, but that was it. There was noise and static about a hit all over the country.
The reason for Double crossing the Pro-invasion faction is that they (the industrial-far right) were not interested in giving Cuba back to Mafia interests and free, independent and prosperous, Spanish-speaking black and Hispanic Catholics. They wanted the war in Vietnam. I also believe that the continued American control of Guantanamo bay was in jeopardy; indeed Guantanamo has never become an issue in all of the intervening years.
This also explains why these same anti-Castro elements showed up at Watergate in 1972 and caused Nixon to soil his shorts. They wanted follow-through on the Cuban invasion.