It would have been possible, but it would have been expensive and required electricity to work. The fact that they accomplished their goal with what amounts to a set of tiny spring-powered mechanical bells is a marvel.

Possibly. Still nott as bad as, “Alexa, order a 12pack of dildos”

Not really sure, doesn’t seem like they’d bother to deaign speakers that make sounds we can’t hear or broadcast them but that doesn’t mean it wasn’t possible

We had a TV that used ultrasonic sound to control the TV, When I was young I could fairly hear the tone from a couple of the buttons, though super faintly, but the dog would cock its head when certain buttons were used.