I would tread very delicately around conspiracy-like discussion topics. People have been banned for less.
Which is why I usually try to keep my own (very well researched) opinion to myself.
I do wonder how the attitude on AH.com would be IF a conspiracy was finally revealed... Especially in the incredibly unlikely event that it turned out, as the OP posits, to have been in any way associated with Castro, which I do not believe.
All of this is here nor there to the OP, though. JFK's assassination is still something of a soft spot (clearly) to the United States and her people. Obama would try to get Castro over here to stand trial and would be supported by all Americans and the Kennedy clan in particular. Castro would never turn himself in, of course.
This would prove difficult but a good start would be putting Castro and his accomplices (Raul?) on the Most Wanted list. If public opinion were strong enough, I could see an invasion as well as a well timed Seal Team Six operation.
Obama becomes a two term president and the Cuban people get Democracy.
Unless something goes terribly wrong. In which case... I dunno.