Nice write up. I like the illustration too. I tried this when the ability came out on Alexa, but found it slow sometimes and non-responive other times. What has been your experience? How fast and how accurate?
I've been meaning to write up a similar proceedure, but the trigger from HE is Google Assistant Relay, rather than OtherHub. Yes, you need a separate Node.js server, but it's not hard or expensive to set one up and many of use have either a node server or a RPi (or several in some instances) already running on our networks.
Why do you say you need a ST hub? You don't. I sold mine months ago and can still do this. You just need ST IDE access. Even if you deleted your location like I did, you just create a new location. Mine for example is just called "Virtual Hub". When adding a Device, the only requirements are Name, ID, Type, Version and Location. You can even configure the devices in the ST app if you need to.
