Yeah, I've also thought this from the beginning. Between what was done to River Tam to make her a sleeper to the stuff they piped into the atmosphere on Miranda to try to make people "better", which caused the creation of Reavers (the equivalent of which in the two Epitaphs seems to be the "Butchers") it can definitely all read as a prequel to Firefly/Serenity, with the further development of the government being itself like a large, multi-planet Rossum Corporation.