2018-2019 Broadway season preview; new plays "The Lifespan of a Fact" and "American Son" announced for the fall; long-planned renovation of the Palace Theatre/hotel complex threatens to shudder "SpongeBob SquarePants"; Natalie Walker ranks all 41 Broadway theatres; Public Theater announces 2018-2019 season; MCC Theater moves to midtown in November; “Carousel” cast recording released