Quick heads up,
using two devices is fine for me. As said, I only had the problem on my prod, still running on the current last raspbee version, without your maintained files. Here the Blitz plug always is only discovered as a pur switch and thus I didn‘t find a way how to get the right settings for reading the measurement values. I already tried to configure it as a sensor device, tested with IDs btw. 1-40, but raspbee wasn‘t able to read anything.
Regarding the siren:
I connected it already to my prod phoscon/deCONZ/Pimatic. Thus surely it will not any longer be discovered by my dev environment. What I tried to say is only, that as long it will take to set up the next official raspbee version (inkl. then officially the shutter and the siren), I‘m steering the siren, connected as light, by the curl commands.
I had to set up this temporary workaround, as my former setup (Hue plug with piezoelectric siren) tended to have wrongly triggered 1sec. alarms, which my wife was not amused about, standing right besides it at one point of time 😅