Nice collection, I love running one night sessions. Everything from "you have been camping and while you were gone the zombie apocalypse happened" to "you are wermacht soldiers alone in a gunner nest, the front just moved past you, make it back". I often use simplified home-brew rules or CoC rules for these short games. One night sessions can also be a lot of fun since they normally are much more dangerous, I boost the chances of dying a lot.
I loved the emperor scenario.