The film is partly autobiographical because many of the events that happened to Hal and Oliver are based on Mike Mills' experiences when his own father came out as gay and began a homosexual relationship after Mike's mother died.
The laryngitis idea used at the costume party is based on a true story that happened to Lou Taylor Pucci, star of Mike Mills' previous film Thumbsucker (2005). Pucci had lost his voice at an audition for Across the Universe (2007) and had indeed gone to a party where he conversed with a girl that he met via a notepad.
Early in the movie, Oliver comments that his dog, Arthur (and other dogs in the same breed, Jack Russell terrier), are very cute to humans and people love them so much that they often put them in TV shows and movies. The most famous "acting" Jack Russells of recent years (Moose, who played "Eddie" in the TV show Frasier (1993) and Moose's son, Enzo, who was the title character in My Dog Skip (2000)) were both owned and trained by the same professional animal trainer, Mathilde de Cagny, who owns and trains Cosmo, the dog playing Arthur.