I really like this project with its great look and feel GUI and ease of use and so its disappointing to read that Mozilla is not continuing with development anymore.
Anyway hopefully there is enough technically able people in the community to contribute to the project and keep it going.
What are the chances of this Aoetec Z-wave Trisensor working with the Gateway?
Have you tried it to see if it works? There is a good chance it will work right out of the box. At least the motion and temperature part. I wouldn’t guarantee the light sensor would work. The Samsung zigbee motion sensors supports motion, temperature, battery and Tamper (whatever that is). They work great with M-IoT.