i highly recommend this. i'm using it to integrate a nodemcu into my HE and it works flawlessly
oops, posted too soon, saw you're already using this.
in terms of usage, you can just use a wifi router to connect all the devices together (it doesn't need to be on the internet as everything will be local.
You could use one of the ESP boards to serve this purpose. it just needs to be a common hub for all the devices to talk (but then you'll need something to hard wire the HE as it's not wifi
