Some of my dungeons get a little "cleared" label on the map when I finish them, others don't. What things need to be done to get that to toggle?

1) All monsters?
2) All monsters and locked chests?
3) All monsters, chests, and other containers, including herbs, and ore?

Do you get respawns in cleared dungeons? If not, could that mean that uncleared dungeons are those that have infinite respawns, or does not having cleared mean I missed something?

I don't know, but when I had cleared a fortress from bandits, when I passed it again 2 days later, it was still empty. Admittedly, I was never very far from it since I even saw dead bodies from weeks ago. So maybe they have respawned now that I'm half the country away from it.