Okay! I finally had a chance to get back to this.
I downloaded those item and save editors and had a lot of fun with them. I incrementally fixed my resistances, as you recommended, and it worked like a charm. It seems to me that the game has difficulty remembering more than one skill bonus on any item, no matter the bonus. I also learned that I cannot remove any type of magic bonus from items, only add certain effects to them, so I just tweaked items with any ONE of the skill bonuses I wanted and had no issues.
I've since finished the game and have started Beyond Divinity. Thanks for your help and Happy New Year!
