A24 and Chernin Entertainment have expanded the cast of their upcoming sci-fi horror feature “The Backrooms,” adding Mark Duplass, Finn Bennett, Lukita Maxwell and Avan Jogia to a lineup that already includes Chiwetel Ejiofor and Renate Reinsve. Production starts this week in Canada under 20-year-old director Kane Parsons, who adapts his viral YouTube series of the same name, viewed more than 190 million times. The project, co-financed and co-produced by the two studios, has not yet set a release date. Separately, Gary Dauberman’s Coin Operated banner has put a new horror title, “Human Remains,” into development. Written by Zachary Donohue, the film centers on a flight transporting the body of a priest who died during an exorcism. Dauberman and company president Mia Maniscalco will produce, with no casting or production timeline disclosed.