As a Z-wave device there isn’t a limit in Alarm.com for number, but there is a limit of 128 devices total built into the panel. You would be able to use 8.
It would be controllable in Alarm.com using the Home or Complete plans.
The included tilt sensors just communicate with the Ecolink garage controller to report status, they don’t connect to the panel as an alarm sensor. A separate sensor compatible with the panel would be needed for this.
You can then program those particular sensors with a long entry delay sensor group to give more time for those doors vs other entry doors.