According to "The Dark Side of Camelot" the original plan for the bay of pigs operation was for Fidel Castro to be killed before the invasion. Let's say Castro gets killed right before the invasion as per the plan. What happens next?
I see a kind of civil war between Che and Raul, so by the time the ill fated exile brigade lands, cuba is in the middle of a civil war, and so the might just be able to gain a foothold and announce that they are the legitimate government of cuba. At which point the US interevenes in what is now a 3 way Cuban Civil War. By mid 62 the anticommunists have more or less seized power.