Bob Dylan threatened to sue the producers for defamation, claiming that the film portrayed him as responsible for Edie Sedgwick's death. Any mention of Dylan was omitted from the script; Hayden Christensen is called Billy Quinn in dialogue and billed in the credits only as "Musician."
The first film Andy Warhol gets Edie to appear in with all the men is Vinyl (1965), his unofficial interpretation of the novel "A Clockwork Orange."
Andy's mother speaks Czech. Andy Warhol's family immigrated from Slovakia, which borders the Czech Republic. Throughout Warhol's life (1928-1987) the Czech and Slovak nations were joined as Czechoslovakia, which existed 1918-1992 (except for WWII, when the Nazis and their enablers governed them as separate puppet states.)
Sienna Miller was cast twice as Edie Sedgwick. The producers dropped her because they felt they needed a "bigger name." She was re-cast partly due to massive publicity from her public break-up with Jude Law.