So far I have 2 of the Safe and Sound (alexa enabled) detectors, these pair with Home Assistant with the HomeKit Controller integration super easily.
I also just bought 4 of the Smoke & CO Battery alarms, these work with HomeKit BLE, so they do not work with Home Assistant. Hopefully if one of these triggers, the two Safe and Sound interlinked units will trip so I can see the alert in HA.
I ordered 4 of the Smoke & CO Hardwire alarms as well, will see when they arrive whether they’re HomeKit Wifi or HomeKit BLE, but based on other comments here I’m guessing it is the latter.