This was wrong. Google is not remembering deleted devices. What actually happened here is almost as stupid. Google strips non-alphanumeric characters from both device names and room names. So “Room Fan + Light” becomes “Room Fan Light” in Google Home. Same with room names, so if you call it “John’s Room” in Google Home you will get “John s Room”. Anyway, I named my virtual light switches “Room Fan Light”, so after the unannounced name translation in sync, it looked like the deleted devices were still present. They were actually the combination “Fan + Light” devices with the plus symbol stripped. I also tried ampersand, comma, and single quotes and all were stripped out. (As an aside, did you know you can sync your Samsung and Google accounts so quickly you get a temp ban from the API? You can.)
So, in summary, everything is working as intended.
For the fans containing smart bulbs I:
- Toggled the device handler setting.
- Deleted the existing child devices. I did this early so I could reuse the names for the virtual switches.
- Created the VDS SmartApp for the switch.
- Had the SmartApp create the virtual switches.
- Deleted the virtual switch for the lights.
- Force a Google sync.
Now for all 5 LZW36 switches I have the appropriate devices in Google Home - including virtual lights-only switches for the fans with dumb bulbs, and fan-only switches for all 5.
I still have the combined fan+light switches in Google Home, which annoyingly lives inside the rooms’ light groups. So when you tell the assistant to turn off a room it hits the combo switch as well and kills the smart bulbs. Because SmartThings killed the ability to selectively disable device syncing earlier this year, all the hacks around this (using different rooms/homes) are dirty.
Honestly this is probably the last straw for SmartThings for me. They really screwed up the Google integration. Between the duplicate devices from Philips Hue (my bridge is nearly full), and now having the combo devices in the light groups, they have regressed my voice commands intolerably. And the light groups I made for the ceiling fan smart bulbs (“ceiling lighs”) don’t sync over at all. As soon as Hubitats are back in stock I am likely to begin the arduous process of moving all of this over. I hope child devices “just work” over in that ecosystem, I am about to start investigating.