Dean and Claire bond over mini golf in this episode. In real life, Kathryn Newton (who plays Claire) is an avid golf player.
When Sam and Dean meet Castiel at the hospital, Dean says. "Three men and a lady. Let's do this." This is a reference to Three Men and a Little Lady (1990); the sequel to the popular comedy Three Men and a Baby (1987).
When Castiel gives Claire the Grumpy Cat stuffed animal he says, "I got it at the Hot Topical." This is a reference to the store Hot Topic, which is known for carrying merchandise from different fandoms, including Supernatural.
The FBI aliases Sam and Castiel are using are Agents Clapton and Page. This is a reference to guitarists Eric Clapton and Jimmy Page, who both used to play in the Sixties blues rock group, as well both also played in John Mayalls Blues Breakers Band. The Yardbirds.
Russell Porter (Ronnie Cartwright) played Dean's suburbs buddy/neighbor Sid in Season 6, episode 1, Exile on Main St. (2010). He was also credited as "Neighbor" in another CW hit, iZombie (2015).