Source: Joe Vogel
I've found the Family Theatre mentioned in issues of Michigan Film Review (scan available at Google Books) as early as 1917, along with three other theaters then operating in Adrian: the Crescent Theatre, the Garden Theatre, and the Opera House. The Family Theatre was located at 136 S. Main Street. The building is still standing, and is currently listed for sale on the web site of Edward Surovell Realtors, Ann Arbor (Google the theater's address to find the listing. There's a photo. ) Newspaperarchive. com has many issues of the Adrian Daily Telegram from 1975 and 1976 with ads for the Studio South I and Studio South II, so the theater was twinned in 1975 or earlier.