Well if they don't mind something a few years old. Yankee Doodle Dandy (1942). Starring Jimmy Cagney as George M Cohan. Jimmy shows off his hoofing skills, which were formidable. Don't know anything more patriotic than this movie. And virtually no violence.
They should actually re-make that. They re-make old movies and sitcoms all the time. There were people involved in the Independence that were in "supporting" roles as it were. Betsy Ross comes to mind and I'm sure there were many more. There is a way to make a movie commemorating this accurately without throwing in violence.