This old chesnut...
Lincoln had two secretaries -- neither named Kennedy.
John Wilkes Booth was from Maryland ... that's kinda north of anywhere we southerners think of as the south. He was also born in 1838, not 1839. He was captured in a tobacco shed, not a warehouse.
Oswald was not called "Lee Harvey Oswald" in his day-to-day life; his full name was issued on APBs and media releases and posterity picked it up. Prior to infamy he was known simply as Lee Oswald.
Marilyn Monroe died on 5 August 1962. JFK was assassinated on 22 November 1963. If he was "with" Monroe a month before his death, there was some shit seriously wrong with that man.
Without even getting into some of the other coincidences (I mean, what are the odds that there would be more than one person in America with the last name Johnson!?!?) the ones that are just factually inaccurate kind of take the impact out of the original message.
Frank