Even though I'm on the "C'mon, it's in Norway" side of the debate, I need to acknowledge that, based on the movie itself, it's Norweg-ish and not explicitly Norwegian.
Now, it's indisputable that the animators went to Norway and incorporated full-on Norwegian fashion and architecture into the film. But, they didn't slavishly copy exact Norwegian things. Just like the town is set in Arendelle and not the real town of Arendal, the film is set in a fictionalized Norway; only, they didn't say Norway. And when they put in FEA and the Sommerhus, it was the imagineers' turn to go to Norway so as to make the architecture as really real Norwegian as possible for the sake of the pavilion.
What I don't get is how some people are perfectly fine with Snow White being German and Pinocchio being Italian even though those movies don't explicitly say "Hey, we're in Germany/Italy!"; but, they have trouble with a clearly Norwegian-ish film being in Norway without it saying, "Hey, we're in Norway."
Well, now, the film is saying, "Hey, we're in Norway!"