Thanks for the clarification @
Dilligaf [thumbs up]
In my original Kodi implementation onto my two AFTV boxes, I was leveraging SMB sources (i.e. smb://username:password@IP_Address/directory/) housed on my Windows 8.1 machine that does not have a Kodi install. This machine was my media 'server' housing my media files. So the Kodi installs on the AFTV's always referenced network shared sources, and shared common libraries via MySQL installed on the Win8.1 machine.
The SMB sources were great for the sharing of media and libraries, but when it came to write access to these sources for things like the Backup addon and other Kodi related writing to shares (see
AFTV: Cannot Write to Windows SMB share ), SMB was not the ultimate means for connecting to my shared network sources. To overcome this, I had to connect via the NFS route by installing haneWIN NFS Server on my Win8.1 machine. I'm a total noob with NFS, but it was my understanding that NFS does not use passwords when connecting, rather some sort of session mount ID to establish connection. With using NFS mounted shares, I've deleted the passwords.xml, and have not seen any negative impact (as of yet). Sorry for this tangent...
I only mention this because both instances of Kodi on my AFTV's reference remote shared sources, not local sources. I say this, because with my noobness of sharing libraries, I was under the impression that with both of my AFTV's in essence being remote clients to the sources, I thought only one of the devices should be configured to do the actual media scraping. I did not know that both devices could do the scraping without a resulting duplicate of the file being injected into the MySQL Db. This new-to-me confirmation that you've just outlined above will be a HUGE help with getting my Kodi implementations successfully working. I was dreading having to spend the time to duplicate my configuration efforts on my second AFTV. Now it appears that a simple backup of one, and restore to the other device will result in a mirror image the other device with any negative result of dupes in the libraries. I hope I'm now understanding this correctly.
I tried to dabble in path substitution for the Thumbnails directory to help manage the limited storage space native to the AFTV, but I wasn't having much success. Once I get the two AFTV's configured correctly (now) and things are running smoothly, I will start back up and continue to explore the path substitution concept.
Touche Dilligaf, thanks for the help and clarifications.