I’ve not have any issues with pet friendly detectors. I have heard cats can cause issues if jumping on high level furniture. Haven’t used the expansion kit but should work with the Veritas if it’s using relays and can be wired into any zone. If going to the expense of the expansion kit may be...
I don’t believe the Veritas range is compatible with any of the Ricochet devices. Have you considered changing the pir’s to pet friendly detectors such as Texecom Capture or Bosch Blueline? This would probably be the cheapest option in my opinion
