[Exxy]

They stack, just not additively. But the first list all increase Phys/Mag Def (and say so in the descriptions), while the others say they reduce damage, which I think is enough of a distinction.

I still think it's better to flat-out say they're two different methods of Damage Reduction/Negation/whatever-overall-term-you-want-to-use than to leave them as "Damage Resistance" and continuously cause confusion. They may be part of the larger goal like I previously mentioned but they play two completely different parts (think of it like having Left and Left instead of Left and Right).