The iconic look Jan gives actor Travis Burns who portrays Steve at the end of the in the 'chow hall' sequence was demonstrated by the real Jan Hurst to actress Caylee Cowan so she could replicate it on screen.
Caylee Cowan did not meet Bonnie Burroughs the actress who portrays adult Jan, until they were called in several months after filming wrapped for ADR work.
Travis Burns and Connor McRaith both read for the part of Steve and met at callbacks, but only Travis Burns read in the room with Caylee Cowan.
Actress Caylee Cowan met Jan Hurst prior to filming in preparation for her role. Caylee took Jan and her granddaughter Darby out for lunch at the Chateau Marmont. In an interview Caylee stated that she was aware of other more seasoned actors such as Margot Robbie not meeting the person they were going to play but Caylee felt it was important for the film and for her character's development.
All footage was shot for this film in 11 days. The scene where Corbin Bernsen and Travis Burns clean the garage and Caylee Cowan defends him on the 4th of July while fire works were going off. The cameras kept rolling and nearly all the audio for those scenes were adjusted with ADR in post.