I had a hard time pairing my Z-Wave plug-in outlets; they have a local control pushbutton on them which I assumed had to be pushed once to pair. I eventually discovered that it required a double click on the pushbutton to pair it (same action required for it to be excluded). When it is paired however, only a single click is required to turn it on or off.
For the my GE Z-Wave wall mounted switches, I found that the Hubitat had to be much closer to the switches when pairing than the ST hub. Three feet does sound like it should be close enough, though; I was able to pair one which was located one floor directly below me in my garage. For mine I did the general exclusion with a minimote and the inclusion with my Hubitat on a long ethernet cord.
Once properly excluded, a single push of the switch (on or off, doesn’t matter) should be enough to pair the device if it is within pairing range. Mine were found right away. Is it possible that they aren’t being properly excluded by ST? I know you said you did a remove from ST; did you actually see an ‘device excluded’ message from ST when doing so or just remove them from the app (I never seemed to get those exclusion messages from ST; I assumed I was out of range. That’s why I used a minimote right next to the switch to to the general exclusion before I removed them from ST. I then tried to operate them from ST to make sure they failed to operate, that told me they were properly excluded).
