At the end of the movie when Gonzo talks with Evie, he can be seen wearing a 'Sons of an Illustrious Father' shirt. This is the name of the band Ezra Miller (Gonzo) is in in real life.
Multiple actors in the film would later star in DC Comics adaptations. Ezra Miller would play Barry Allen/The Flash in the DC Extended Universe, Zoe Kravitz would play Selina Kyle/Catwoman in The Batman (2021), Conor Leslie would play Donna Troy/Wonder Girl in Titans (2018-) and Jesse McCartney would voice Dick Grayson/Nightwing in Young Justice (2010-).
Jordan Lane Price's debut.