Thanks...Let's see, lots of questions:
1) Which Fire tablets are these (older models?), and it's unclear why they are both rooted and running stock OS.
I'm using 2017 HD 10s and HD8s. I preferred rootable models from the start because I knew I wanted the flexibility to root just in case. I deliberately chose old models because they are easier to root, cheap (costs add up when you have 5-10 of these installed), and they are easy to source.
At the end of the day, I'm using root to debloat the tablets, control charging limits, and remote wake functions. Root is not necessary though.
I tried some 3rd party roms, but I never got them to run quite as fast as the stock amazon OS (after debloating). Could be I just got a bad flash though. Many others have reported good results on custom ROMs like lineage.
2) Which POE to USB adaptors did you use? Did you run this wiring in existing walls? If you happen to have any photos during installation, that would be great!\\
I'm using the POE adapters included with the makes by mike mounts linked above. They're not true POE, they just convert POE voltage down to 5v. You could do the same with a buck booster or similar.
The really nice thing about the makes by mike power adapters is they come with right angle USB plugs, so the mount is clean with minimal cord stress. I'll see if I have any wiring photos somewhere
Also, I saw in another thread that you were having problems with BI. Did that get resolved?
Yes, I was having trouble with the BI webserver crashing. Ultimately I did get it solved, and ken tried to help, but unfortunately it required a full wipe of my BI OS