Clockwise from left, Nathan Lee Graham, Nathan Lane and Matt Bomer of the sitcom “Mid-Century Modern.” A fourth member of the main cast, Linda Lavin, died after much of the first season was shot.

Mid-Century Modern co-creator Max Mutchnick has revealed how the late Linda Lavin’s character Sybil Schneiderman will be written off the upcoming Hulu comedy series. The title of Lavin’s final ...