The location of the bar that Pierce liked to work in and that Maddie/Kay worked in is The Prince in Koreatown. It has also been used in other shows like New Girl (2011).
When Dan and Lucifer are speaking in the van, the sound equipment picks up their voices. A spectral analyzer can be seen over Dan's shoulder, responding as they speak.
Tricia Helfer (Charlotte), Lesley-Ann Brandt (Mazikeen) and Joshua Gomez (Neil Berger) have all appeared in the TV show, Chuck (2007). They played Agent Alex Forrest, Fatima Tazi and Morgan Grimes respectively.
The Chance's Chocolates radio bit is a reference to War of the Roses on the Johnjay and Rich morning show.
Pierce's flashbacks to his 1950s cop-drinking hangout are eventually revealed to be at the Adams Bar - a real family haunt for Cain, in fact, as a member of the original Adam's Family.