Other mistake: In the scene where Jesse enters Monica's apartment, he consults her calendar to see in which class she is in school that day. There's nothing unusual about this until you look closely at the calendar and see that time time is early/mid August. Did her school's academic year run differently from other schools' years, or was she taking summer classes? The latter doesn't seem likely.
Jesse Lujack: I say Monica, you ever been to Mexico, honey?
Jesse Lujack: I say Monica, darlin', you coming to Mexico with me?
Jesse Lujack: Monica, you coming to Mexico with me.
Jesse Lujack: Me and Monica.
Jesse Lujack: Cos I'm gonna tell you how it's gonna be.
Jesse Lujack: Mon-Monica and me.
Jesse Lujack: Me and Monica! Yeah, me and Monica go to Méjico.