Thanks for taking the time to write such a detailed reply, pwm. I've edited my earlier posts to accurately convey mappings as they are set up.
Here's the relevant part of the docker config:
Scenario 1: Point well taken. I do understand that having multiple mappings opens up the kinds of problems one can have when copying from disk shares to user shares (don't do it!) As I'm only using this docker to move files from user share to user share, OR unassigned device to user share, I don't think I'm opening myself up to that issue in this case.
Scenario 2: I don't believe I've set myself up for issues here with my behavior so far, but understood how it would be easy to. I will ponder this part of your response again in the morning after a full night's sleep
At the end of the day, I'll probably switch the container path "/media" to point to host path "/mnt/user", and only access unassigned devices through the container path "/UNASSIGNED" which points to host path "/mnt/disks" which is behaving just fine. I hope I can get to a solid understanding of why my current container path "/media/disks" shows my unassigned devices as folders, but points to rootfs for each of them....