This problem has been fixed in version 2.3.1
The “Choose Devices” page lists all the capabilities to ensure you’ll be able to add all your devices, but which field you choose the device from has no affect on which page it appears on. (lights are the only exception)
All devices that support the switch capability will appear on the Switches page. If you don’t want your sirens to appear on the switches page, go into the “Display Settings” screen and exclude them for that capability.
I know that seems kind of strange, but excluding a device that appears somewhere you don’t want it is a lot easier than selecting every device multiple times to get them on all the screens you do want them.