WhIle there is a forum for Linux Ideas, I was unable to start a new thread there (don't know why).

So Here is the thread to follow what is to develop out of this idea. (I am not sure if this is workable, so the first question relates to 2 possible problems, and if they apply or not.

The basic Idea:

too set up a pair of hard drives in a firmware controlled RAID0 external box that can be physically plugged in one of several computers from time to time, and use that to make a hardware pluggable repository.

Q1) If such a repository were to be created, could it be done so that when it was plugged from one computer to another, there would be no need to use a terminal and CHOWN to change owners?

Q2) If it were only plugged in where it had access to the internet from time to time, would it then automatically update itself as soon as it was plugged into a computer thqat was connected to the internet?

...and this is called a "local repository", and can be ANY sort of media, from DVD to a USB Thumbdrive. Commonly in use today:
https://wiki.centos.org/HowTos/CreateLocalRepos
Since only root *SHOULD* be able to update systems, the root user is always present, and always the same. Not an issue
How would it? All that is, is a collection of RPM's and other software. Unless you have some script or some program that checks the various internet sources for updates, it won't do anything.