Drew Seeley is 10 years and 3 months older than Selena Gomez, with him being 26 when the film was released and her being just 16
The news segment that Britt and Bree watch shows concert clips that appear to be from the High School Musical concert tour that Drew Seeley participated in.
Katharine Isabelle and Emily Perkins, who play sisters Bree and Britt respectively, also starred as the title character and her sister in all three of the "Ginger Snaps" movies, a Canadian horror movie trilogy. (These are Ginger Snaps (2000), Ginger Snaps 2: Unleashed (2004), and Ginger Snaps Back: The Beginning (2004).)
According to the cast, the finale dance number was the most difficult during filming.