The fall lineup of Off Broadway productions continues to nail down casting, with the tuner version of 2006 film “Once” — now set to star Steve Kazee and Cristin Milioti — among the handful of shows to land thesps in recent days.Kazee (“110 in the Shade”) and Milioti (“Stunning,” “The Lieutenant of Inishmore”) will play the central couple in the show, which follows the romance between an Irish musician and Czech immigrant. The stage version will incorporate songs from the movie version, which starred songwriters Glen Hansard and Marketa Irglova. David Patrick Kelly, David Abeles and Anne L. Nathan also are among the cast of the show, helmed by John Tiffany and choreographed by Steven Hoggett, the duo behind international hit “Black Watch.” Show already has commercial producers poised to move the tuner to Broadway, should the Off Broadway bow, which begins previews Nov. 15 ahead of a Dec. 6 opening at New York Theater Workshop, prove a success. The Ellen Burstyn-toplined world preem of David Bar Katz’s play “The Atmostphere of Memory” also has filled out its cast, with John Glover and Max Casella among the performers signing on for the LAByrinth Theater Company production. Pam MacKinnon-helmed staging begins previews Oct. 15 and opens Oct. 30 at the Bank Street Theater. At Off Broadway’s Public Theater, Tony winner Bill Irwin (“Who’s Afraid of Virginia Woolf?”), Frank Wood (“Angels in America”) and Kristen Connolly complete a cast that already includes Sam Waterston, John Douglas Thompson and Kelli O’Hara. Irwin will play the fool in the show, directed by James Macdonald and gearing up to start perfs Oct. 18.On Broadway, Rosie Benton (“Accent on Youth”) rounds out the cast of “Stick Fly,” the incoming play starring Dule Hill and Mekhi Phifer and co-produced by Alicia Keys. Kenny Leon directs the show, which opens Dec. 8 at the Cort Theater.