Great easy guide .. I just skipped the media folders part and used the mount points via the web gui. I was using the plex plugin for a long time and my OCD got the better part of me when I couldn't update the jail to 12.2 and was stuck on 12.1.
I had one little issue where plex wouldn't start after adding mount points, but running:
iocage exec 3DPlexPass service plexmediaserver_plexpass start
again seem to correct the issue and plex starts on it's own again after stopping the jail.
This easy setup combined with:
wget
https://raw.githubusercontent.com/mstinaff/PMS_Updater/master/PMS_Updater.sh
sh PMS_Updater.sh -v -a
..now allows me to stay up to date with the whole ball of wax!