What am I allowed to do with HS4-PI installation?

[eaf]

Since I'd opened this topic I saw in other posts that a generic HS4 Linux tarball can be installed on RPI, that it's the license type that determines HS4-PI lower set of features, not binary distribution, so this pretty much means that yeah, I can grab /usr/local/HomeSeer from the RPI image or just get a generic HS4 tarball and put it on another RPI. The OS, mono, etc can be upgraded at my own risk, and as for non-root I guess, I'll adjust directory and /dev/ttyACM0 permissions and will make it work.

[eaf]

I downloaded, flashed, booted, played and even upgraded the HS4-PI image...

Generally I feel a little uneasy about the entire RPI being managed from HS4. Looks like HS4 tries messing with GPIO, turn some LEDs on and off from /etc/rc.local before and after starting the actual HS4 process, control TZ and generally just feels at home running as root.

Could someone please clarify what I can or should not do with this RPI?

1) Can I install other software on it like my MQTT broker or Domoticz w/o fearing that another HS4 upgrade will blow them up?
2) Am I supposed to or should I separately upgrade RPI (apt update, apt upgrade, etc)?
3) Does HD4 Setup->General->Update change only files under /usr/local/HomeSeer or does it attempt to modify the rest of the system as well?
4) Can I just tar /usr/local/HomeSeer and move it to another system thereby abandoning the OS image that I downloaded from HomeSeer?
5) Can I run HS as non-root user?

Also, I've spent quite some time trying to figure out why my Aeotec Z-Wave stick wouldn't show up under /dev/ttyACM0 and why HS4 would only see /dev/ttyS0 for serial ports. Ran into some topics suggesting to use external USB hubs with RPI4, and that indeed helped, but I just can't believe that I'd need a hub to make a USB serial device appear in the system. Is this hub the only workaround available?

Thanks!