In Porter and Ellard’s “Permanent Fixtures,” a woman examines her compulsion to hold onto everything. In Steffler and Rinkema’s “Killing Robby Jenkins,” a young woman contending with a vindictive ex laments her world is ending, and her mother tries to shield her from the fact that, indeed, the world is literally ending. In “Too Pregnant for Mice or Men,” Ania and Diane Payne show us a home renovation project that goes wildly askew.