DaddyTimesTwo: May I pontificate? (watches computer screen intently) Thanks!
I'm a dad of three children born inside a span of twelve and a half months. Welcome to the way-too-tired-and-guilt-ridden-because-of-it club. The mirror thing didn't work for long in the Soup Pot either, largely because after a certain stage of cognitive development the little wombats start to view it as a tool for whining Research and Development. Sounds like your daughter is experimenting with promising developments in the field. Good for her.
I don't know if it'll work for you but I will tell you my next move after the mirror stopped working. Essentially my strategy was to, through sheer weirdness, distract the little so-and-so's from their mission. I'd say, for example, "Oh! You're sad? Time to make toast!" Or, "Better make some soap bubbles!(this was especially handy when we had dirty dishes in the sink) Or, "What color are you sad? Red? We'd better draw a bright red picture right now!" Distraction (again, of course, if there isn't an immediate, obvious remedy) usually works. It does have the disadvantage of innoculating your child to, and making them very good at, non-sequitur weirdness