The creator planned Toph as a man...

..so maybe it was early woke propaganda.

I'm not a big enough fan to follow the behind the scenes stuff so I'm not sure if you're just joking about the theater scene or if she was originally going to be a male character, but...

Could have just been a natural change during the creative process, y'know? Parents tend to be more protective over their daughters which fits well with her being so severely sheltered. Just a random guess, no idea what their actual inspiration was, may have been for sex diversity's sake (pandering) after all. Never liked the school of thought where you /have/ to include an equal amount of girls in your main cast.

At the very least, I'd say she's a well written tomboy character and I'm glad they didn't try to make her gay in Korra. I never liked The Legend of Korra very much, the writing sucked comparatively, didn't even finish it.