>Let's make that possible. Rembrandt, stuck with young Adolf, moves on to one of the dealers he tries to sell his daubs to. By the time he is able to take control of a host, the ghost on a mission will thus have a wide, if biased, knowledge of the contemporary world.
And the Schicklegrubers are (for sake of argument) just the sort
of people the ghosts want to use.
Yes, but unless you want to posit a supernatural world for which there can be no disproof then a ghost cannot be aware of wanting without a body in which to be aware. That's a bit chicken and egg, so I have to imagine that the first infection is purely random. From the ghost's point of view, they are suddenly looking at the world through the eyes of someone who will happen to be nearby 100 years in the future, and who is completely unaware of the ghost's presense.
Then there are several possibilities:
1 The ghost loses interest and turns off.
2 The ghost begins to understand what is happening, begins to take an interest in someone else and to wonder what it would be like to see the world through their eyes, and finds it can change hosts.
3 Perhaps after several changes of host, the ghost finds someone they want to possess. After some success in that direction they are no longer able to change hosts, and so must take their chances at another awakening in the far future when their host dies.
There is no grand overall plan. A ghost passes unbeknownst from friend to friend, student to master to visiting expert, following only their own needs and what they have learned about the new world along the way.
Rembrandt wakes in 1769, the same year in which Sir Joshua Reynolds was knighted. Some time later James Northcote, a student of Reynolds, begins to paint in a style inspired by the Old Master. How is it received?
Napoleon wakes in 1921. In his absence his offspring have proved a disappointment, and France has been invaded twice. If he could make a radio broadcast from the Eiffel tower, what would he say? Or perhaps he looks for opportunites in the political unrest of Germany. Napoleon in charge of Barbarossa - could he do any better?
Abraham Lincoln wakes in 1965, right in the middle of the Civil Rights Era. Interesting.