Where are Luke, Leia, Han and Ben Solo during The Mandalorian?

I adore The Mandalorian. It’s such a great show and a joy to watch. As Mando looks for a Jedi to train The Child, some fans have begun to wonder about the whereabouts of the most famous Jedi Master of time, Luke Skywalker. Where is Luke, his sister Leia, his friend Han and their son, Ben Solo — who goes onto become Kylo Ren, the villain of the sequel trilogy — at the time of The Mandalorian?

The Mandalorian is set in 9 ABY (After the Battle of Yavin). The Battle of Endor, the climatic battle ...