Running Hassio on a RPi3, I have HomeKit working—well, I did, but that’s a separate issue—and the Ring Alarm add-on working, with my Ring Alarm sensors and control panel showing as badges in the HA UI, with the control panel controllable between modes.
I cannot, however, see these Ring Alarm devices in the iOS Home app. (I do see Alexa Guard as an alarm control panel in Home, though, so I don’t think it’s a domain or device type incompatibility.)
I got mine working. I think what did it was adding a 10 second HomeKit start delay. I already had a start delay in automations.yaml, waiting for ’zwave.network_ready’ (as is mentioned in the HA HomeKit documentation). I didn’t realize HomeKit also needed Ring/MQTT devices to be ready as well. Or at least I assume that’s what was going on.
So now that I have an additional ’delay: 00:00:10’ in there it works…most of the time.