Alright, GOOD NEWS! I figured that if you press B on the keyboard, you access a menu from where you CAN use the Orb and the Key! Now, I wonder why I can't use them from the inventory? I always managed to use the Blessed Icon from the inventory, I never had to use the B button, why would I do for the Orb and the Key? Also, being the dumbass I am, of course, I missed the tutorial explaining the utility of the B button (I started a new game up to that point just to be sure).
*sigh*
Anyway, finished the game, blown the final boss' ass (Shopping Spree is broken), got the best ending. And I like how it turned out. Soooo... Good job on that. That doesn't solve the softlock and other problems, but I had fun with your game overall.
Good job with it!