... What I don't understand, is in the Q&A, Jim calls Kringle a "mantle" but in the book he calls Kringle a "person," in the body of Odin. Plus a lot of talk about protocol.
Harry is an "unreliable narrator," and has limited understanding of things.
I think you are inferring more from & about the Harry-POV than actually is stated.
The WoJ is clear: "Kringle" is a faerie mantle (specifically, Winterfae).
... Which brings me to what Jim says next about Odin, how I read it is while in theory Kringle has to obey Mab, Odin/Kringle doesn't mind giving her the finger on occasion if her agenda doesn't match his. In Skin Game their agendas matched, what would be interesting is if Mab gave Kringle an order which didn't match Odin's agenda.. Then we would see how readily Kringle would obey Mab.. That's where all the talk of protocol to prevent conflict comes in I think.
Odin knows the trick of taking off a mantle without dying, of holding onto it, of putting it back on again at need. If Odin is wearing the Kringlemantle, he has to obey Mab; if Odin isn't willing to obey Mab, he just
takes off the Kringlemantle (and loses the Christmas-y Kringlepowers... but he's still f'ing
Odin the Allfather, who was ancient before mortal-Mab first joined the fae; and things probably just got
really tense...) .
Harry doesn't stop being Harry, just because he's got the WK mantle (I'm expecting him to learn the off-and-on mantle trick from Odin).
Reading between the lines, I think Odin & Mab probably both put in a bit of effort to see to it that Odin's interests do not seriously conflict with Mab's interests, during the time that Odin is wearing the Kringlemantle: neither one of them wants that conflict, but neither one of them could avoid it under the
rightwrong circumstances.