I get that somebody unfroze the kids and gave them the reigns, but how is Sheriff Pope back? Or is he solely in flashbacks?

So far it looks like a replay of S.1 with a whole new set WP citizens who have no idea of what happened. This could get boring real quick. The books laid out a clear depiction of what WP's problems were: the location is too far north (Idaho) to grow enough food to sustain the population. They all went back to sleep and were supposed to wake up some time later in order to try to scout outside the fence and eventually find a way to relocate in a region where they could have a proper agrarian society that would become entirely self sustaining. For the series to move along, they need to send a bunch of heavily armed people outside the walls to make their way out towards what used to be Kansas or something.