Must be thought to be dead for over four days.

Must be thought to have died with a fairly high degree of certainty. Most people wouldn't be all that surprised to discover D.B. Cooper didn't die in 1971, but they'd be surprised to learn Jimmy Hoffa survived a while after his disappearance, or Heinrich Muller after the end of WWII.

Must be famous enough to have a Wikipedia page before they were revealed to be alive.

Resolves YES even if they are dead, as long as they lived significantly longer than people thought they did.

1900 or later, no ancient history.

May resolve to a probability in the case of uncertainty at close time.

Some wiggle room in how this gets resolved so I won't bet.