So how about my other question then: can ADC/Qolsys and an automation controller both register and control the same z-wave devices at the same time?
Maybe. It has been possible in the past on systems, including the IQ Panel 2/2+, and generally you have access to compatible devices in ADC and then the primary controller acts as a parallel control network. (it would not be able to use the panel sensor status though. That is not shared, so your specific example wouldn’t work.)
The interaction as a secondary Z-wave controller is not required for Z-wave certification and is not yet officially tested on the IQ Panel 4 afaik. We have had users attempt to link Smartthings with the IQ Panel 4 and fail for example, but it’s not clear if the issue is the Smartthings software or the panel learning functions on the IQ Panel based on the testing.