Possible Additions:
It occurs to me that all 3 of these devices are best implimented as something that is on the center of the ceiling of each room in the house. It would be rather annoying and ugly to run wires and mount all 3 separately to the ceiling, so this seems like an obvious and ideal combination for home use. It would have to be wired to power to support continuous operation of these functions, but it would ideally also include a backup battery so that most of the features would continue during a short term power outage and then everything would power down so that the battery could allow the smoke detector to continue to function for longer on battery only power.
Since power is the only required connectivity, it could be a drop in replacement for powered Smoke Detectors.
Ideally there would be an option for Gigabit Ethernet connectivity to reduce the need for wireless mesh in cases where Ethernet can be run easily, as well as if the device is installed in non-ceiling use cases. If it supported Power over Ethernet, then there is the possibility of running only a single wire for new locations. If powerline ethernet was supported as well, then that would provide better communication options in cases where there is power but not ethernet.