Yes to all. The secret? Sleep schedule. I have trouble sleeping outside of the sleep schedule hours even if I'm very tired; I need to be near the point of exhaustion for that to be actually possible. On the other hand, it's so overwhelmingly strong I can fall asleep in almost all circumstances (severe emotional damage incurred before sleep notwithstanding). Now as for the restfulness of these scenarios, I can only attest that 1 and 3 lead to somewhat restful sleep; the others I've never actually experienced.