So, got my two Nanoleaf A19 Thread bulbs, screwed them in, initialized them with the tiny separate QR code included in the box, and they work better than any switches/smartplugs I’ve got. Control through the Home app on my iPhone7 is instant, accurate, and just works. First time I’ve been this satisfied with ANY Homekit device.
I also just got last Friday my new AppleTV4K, also with Thread and set up as a Homekit hub. So now I have the AppleTV, the two Nanoleaf bulbs, one WeMo light switch, and seven WeMo smartplugs all with Thread. The WeMo’s all take several seconds to activate though for whatever reason as opposed to the instant action of the Nanoleafs. I see getting rid of the WeMo’s soon and instead just using more Nanoleaf bulbs instead of smartplugs. As a side benefit, I’m guessing (hoping) more Thread devices will increase the performance of each Thread device in the home.