In the first scene in which the policeman arrests Paul Rudd for selling marijuana, since the policeman asked Paul Rudd for it, it would be considered entrapment and therefore not a legal arrest.
The order of the siblings is never revealed in the film. However at the time of release Paul Rudd was 42, Emily Mortimer 39, Elizabeth Banks 37, and Zooey Deschanel 31. Shirley Knight, who plays their mother, was 75.
Elizabeth Banks and Paul Rudd, who play siblings in this movie, played a couple in Role Models (2008) and Wet Hot American Summer (2001).
Rashida Jones and Paul Rudd previously played a couple in I Love You, Man (2009). Here she plays Ned's sister's girlfriend.