First play or musical: Yikes. I know my first two musicals on film were "South Pacific" (at a drive-in!) and "Porgy and Bess" -- not sure which was first. But that wasn't the question, now, was it? How ANNOYING of me.
Okay, first musical on stage was a summer stock or a touring company doing "Kismet" in Columbus, Ohio. I have the program...somewhere. Kenley Players, maybe? The answer is waiting in some drawer. If that wasn't the first, then it's a community production of "South Pacific in Fort Lauderdale in the cavernous War Memorial Auditorium. This will be late 1960 or early 1961.
For Broadway, it was Ginger Rogers in "Hello, Dolly", then I saw Channing do it on tour at the Dade County Auditorium in Miami.
First non-musical play, though?? -- Annoyingly, I HAVE NO IDEA!
Have to think about this.