DL Cancelled service

What actually still works locally if you cancel DL monitoring service? Assume app is a no. What about the control panel, sensors, camera etc.? Does the alarm still work if you "arm" the system or only the chirps when a sensor is tripped? Does dlc show a constant alarm status?

Are sensors, camera and door lock all ATT proprietary - i.e. can't be used with any other system or able to reprogram the z-wave equipment?