The hotel wedding that Tim and his friends crash is for two women. Same-sex marriage has been legal in the state of Iowa since April 3, 2009, when the Iowa Supreme Court unanimously upheld a lower court's ruling that there was no legitimate governmental interest in denying gay and lesbian Iowa citizens civil marriage licenses.
Isiah Whitlock Jr.'s character Ronald Wilke references the character Omar from the TV show The Wire (2002). He played the character State Sen. R. Clayton 'Clay' Davis on the TV series. According to Whitlock, the 'Wire' references were in the script before he was cast, and they decided to keep them in place as an in-joke for fans of both Whitlock and his former show.
The name of the young call girl, "Bree," is an allusion to the movie "Klute," where Jane Fonda plays a call girl named Bree Daniels, and becomes romantically involved with a square private eye, played by Donald Southerland. In Cedar Rapids, Bree and square insurance salesman, Tim Lippe, almost get to that point, too.