How would you react if these were the next five Presidents?

[Mister Mets]

It seems unlikely that they'll all hold elected office now.

We could see what the next five Presidents were doing in 1962 (a relatively volatile time.)
JFK was President
LBJ was Vice President (checks out)
Richard Nixon was a former Vice President running for Governor (checks out)
Gerald Ford was a Congressman prominent enough to be on the verge of holding leadership posts (checks out)
Jimmy Carter was a candidate for State Senate in Georgia
Ronald Reagan was an actor who finished his last term as President of the Screen Actors Guild, who had just got fired from General Electric for criticizing big government.

[Mister Mets]

I would be about as surprised as I would have been at past likely future presidents, such as Henry Clay, Daniel Webster, James Blaine, William Jennings Bryan, Thomas E. Dewey, Ted Kennedy, Jessie Jackson, Dick Gephardt, Mario Cuomo, Bob Dole, Al Gore, and Hillary Clinton.

It's be hard to predict presidents years in advance.

So let's look at early 1896.
McKinley was a top figure in a key swing state.
Teddy Roosevelt was a hero/ President of the New York City Board of Police Commissioners.
Taft was a judge.
Wilson was a political science professor at Princeton.
Harding had lost a race for auditor.

We're currently in a period where we've had three presidents in a row serve two full terms, so it's pretty likely that people we've never heard of, who haven't done the things that'll bring them to national prominence, will be among the first five successors to Trump, especially since the last of the bunch might not take the White House for thirty years (and that's factoring in potential resignations/ one-termers.)