Hello. Just making a placeholder here as it seems you have similar problems like me 
https://community.homey.app/t/compatible-linked-smoke-alarms-european-market/
I also want to add “any” smart smoke alarm to my Homey without having to use an extra hub. And as a bonus I want it to work as a siren (to have the possibility to trigger the alarm from Homey), but for now I have no solution to the problem 
