The missiles were placed in Cuba in secret. We did not know until they were discovered by a routine U2 flight. Therefore, Reagan would have had no bearing on it. However, anyone without the intellect of JFK in charge at the time would likely have resulted in a nuclear war. Ronny would have likely invaded Cuba. Unbeknown to us, the Russians had tactical Nuclear missiles (under Russian control, not Cuban), who in later interviews stated they would have fired them if Cuba had been invaded by the U.S. Therefore, Ronny at the reins would have been a disaster.. Of course, the Russkis would never placed missiles in Cuba under Reagan. They did so under JFK because he portrayed weakness. Reagan never portrayed weakness.
Note: I was in the Army at the time, am well aware of the details.