In an earlier episode, the bloody milkshake is half full when made in the kitchen but full at the top of the stairs. How did more shake into the containers?
The town police are described as "sheriffs", as seen by their cars which say "Annville Sheriff" on them. But in the US, Sheriff's Departments are organized on the county level, not the city or town level. However, some small towns in Texas do not have a police force and law enforcement is the responsibility of their county's Sheriff's Department.
Humperdoo is introduced as the twenty-fifth great grandson of Jesus Christ. This would mean that only twenty-seven generations were needed to reach the present day. Assuming that the historical Jesus died somewhere around 30 CE it would mean that the average age of fatherhood would need to be around seventy-five years old. However, this could be explained by the supernatural nature of the lineage or the show in general.