1) Thinking more about this, especially now that I have a random non-group NPC attempting to open my barricaded patio door infinitely from outside the home, I think NPCs should be given a stuck pathfinding check. If after a certain amount of in-game time they haven't moved, they could be forced to abandon their current task, find a different target job, seek out a different house entirely, etc.

2) I'm with some regularity encountering NPCs who are on rooftops, who stay there forever -- the last one died when a fire broke out and simply stayed on the roof and burned (honestly, the fire was *not* intentional -- I was playing with Cheat Menu and discovered just how much zombies can spread flames). I'm less certain whether NPCs appear on roofs due to a feature or a bug, but in any case, would it be possible to convince NPCs to jump down (and risk injury) once there are no zombies nearby?