I’ve gone ahead and ordered one of those Halos - try that out & see how it goes.
But I think I’m ultimately going to go this route:
So that will be an expansion of the basic premise of creating the Smart Things integration but utilizing Kidde’s own WIreless Interconnecting devices as the backbone. That means I can use one Hard-Wired device as the Co-ordinator and Relay(s) Trigger for the Contact Switches into ST and Battery Modules for the Wireless Satelltites which will be located in each Bedroom.