Well, except for Narrative Opportunities are built into the rules but are a "mechanical resolution" only because they are tied to die rolls, so clearly it's intending to be a hybrid. And it allows and encourages intentional failures on die rolls. Your definitions of "narrative gameplay" and"mechanical resolution" are nothing more than a nebulous construct, not some set-in-stone definition. By definition, every game has mechanics, even one as simplistic and free-form as Mouseguard.
I mean, you can try to split all the hairs you want though.