Thanks for the info. I thought I hit reply the other day... but I guess I didn't.
It seems like itch erases everything on each new game update, so I need to store the game settings somewhere outside of the itch folder any how. :( So for Itch game installations, I may have to create a <mydocs>/<game>/Itch/Addons folder for stuff to be stored that won't get lost on each new game update. That would then require the users to use Curse or some such third party mod hosting/client for mods/themes/etc.
Thanks for the info! I definitely have some things to think about.