I don't trust Ubisoft to have the degree of opsec necessary to prevent something like this. Hell, I don't trust Ubisoft to have the degree of opsec necessary to notice it happened ex post facto.
Open/closed source has nothing to do with it. If this project is using Nintendo IP without permission (and I see no evidence this is a licensed product) Nintendo will definitely go after them.
If you click on an inventory slot on your character sheet it will pop up a window with all available items anywhere in your inventory that can be equipped there.
What exactly do they mean by "flagship"? The Escapist had Zero Punctuation and... that's about it. Aside from some Yahtzee Croshaw podcasts, I can't think of anything else worth watching on there.