The opening scene which showed a close up of Beth's (Emily Kinney) face while she opened her eyes was inspired by the scene from the pilot episode, Days Gone Bye (2010), in which Rick (Andrew Lincoln) essentially does the same thing.
Vincent Martella appeared in Season 4. He and Tyler James Williams were both main characters in Everybody Hates Chris (2005).
The large painting in Dr Steven Edwards's office is Caravaggio's The Denial of St. Peter, circa 1610. It is presently housed in the Museum of Modern Art in NYC and would not have been found in the trash on the street in Atlanta as Edwards claimed.