Great list.....but a duck's quack does echo. It's a classic myth.
You can only distinguish a sudden, short noise like a hand clap when listening for an echo, but if you try and distinguish something like a buzzing or drone you will not be able to. A duck's quack is a wave form that starts soft then builds and tails of slowly, this is maybe why this myth came about and was popularized as a piece of comedy, like bubble bees mathematically shouldn't be able to fly etc.. Unfortunately some people believe these things without thinking to hard..... a bit like SEO in many ways