"As for the "Did it work?" part: yes, it did. Kind of. Our assembly may have lacked elegance but it did the trick. Sadly the key phrase wasn't always recognised, and the thing was easily flummoxed by background noise, but the makers acknowledge that more training is needed to bring the machine learning models up to speed, and they hope the community will get involved."
Sounds like every single "voice recognition" tool I've ever used in my entire life.
But I can't see why you'd go to the effort of baffling Alexa with lots of other gadgets when you could just use the thing you have that recognises voice commands (as well as anything else) and make your own smart assistant. I'm sure there must be a project somewhere already, if not a dozen of them. And with something like OpenHAB, you could easily make it control anything you liked. Even Alexa/Home-compatible devices.