Actor Evan Casey was two weeks into the run of “The Amateurs” at Olney Theatre Center — a play set during a 14th-century plague — when the Maryland venue closed because of coronavirus concerns. His actress wife, Tracy Lynn Olivera, was deep into her duties as assistant director of “Guys and Dolls,” the spring production at Ford’s Theatre, when that musical was shut down. It has been rescheduled for next spring.