Zekrom and Reshiram both work for N. Maybe one more obviously than the other, but still.
N's ideal is that of a world where Pokemon are never hurt, and to do that, Pokemon need to be separated from people. The protagonist shows him the truth - that Pokemon belong with people.
N knows the truth; people hurt Pokemon, and those people need to be separated from their Pokemon, and those Pokemon need to be protected. After all, he's seen Pokemon abused by people. The protagonist represents the ideal, a trainer who cares for their Pokemon and treats them as friends and allies.
Plasma is an ionized gas, and is most commonly associated with electricity. Lightning is a form of plasma. However. plasma can also be produced by intense heat, and fire is also a form of plasma.
Yes, it's easier for most people to justify N with Zekrom, and the protagonist with Reshiram, but neither of them makes more sense than the other. Canon is your choice. Personally, since I got White and W2, I believe White to be canon. You can choose whatever you want.
