It is correct as opening the cover tests the tamper switch, battery and hold off. Some low end panels overide this on entering engineer mode but this prevents sab tests
Pet sensors are not best especially with cats changing height as they appear much taller to the sensor. How close to the sensor is the cat when it alarms.
Best bet in any pet environment is perimeter protection
Yes as above looks like a bus or device issue. Assuming you have checked and tested the cabling then just remove one device at a time. You could also split the busses as iirc the 96 has 2 busses
No it can't. Either run a cable to it or get a flashing led kit
I.e.
https://www.securitywarehouse.co.uk/catalog/bentley-double-flash-unit-with-two-leds-p-3742.html