*snort* I'm talking "reasonably-intelligent" in terms of actual intelligence--I didn't say he has the slightest bit of common sense, because he clearly does not. In terms of intelligence I've got him pegged for slightly above average: he's clearly quite articulate in his native Swedish, and demonstrates a broad vocabulary and an ability to retain a lot of random information (as when he's playing tour guide for Tuuri). Plus he enjoys reading and academics, which is not something you enjoy if you aren't good at it. He's not near as bright a spark as, say, Tuuri, but he can keep up.
And oh yes, I've no doubt that his parents coddled him in one way or another--and all of the examples you gave would fit with Emil's personality and the very little we know about his parents. They just strike me as... hmm. Peculiarly neglectful. The two can--and often do--go together.
Oh, sorry, I measure 'actual intellgience' by the amount of common sense, and from what I've seen, he is a complete idiot. It's not just that he thought that his face was made from a different material than the rest of his body. He does a lot of thinks without THINKING first. He assumes things (which turn out to be wrong), speaks without thinking twice (and insults people in the process). Sure, when he tries his best to make a good impression he is a lot more careful, but it seems that when he relaxes, he just floats to his own stupid world and stops thinking.
These are all qualities that would lower his 'actual intelligence' as YOU mean it. He wouldn't ponder enough on any (test or not) question before answering it. He wouldn't try to see a problem from different points of view. He wouldn't see things collectively. He would make wrong assumptions. Sure, he may speak Swedish well, but being good in your native language does not make you 'slightly above average smart'. How is he in math? Physics? Other languages? Does he write poems?
Besides, the information he told Tuuri was about his native country and a city he had lived in for a large period of time. These are not signs of great memory. It seems Swedish are proud of their achievements in the post-rash world, and therefore quite natural that they tell their kids all the time how great they are. Emil would hear about these things very often.
I'm not sure why you assume he enjoyed reading and studying. Yes, he said that he is a 'brainiac', but I don't take his opinion seriously on the matter. I think he just meant that he is 'super smart', what with 'excelling with no effort at all'. 'Excelling with no effort at all' can mean two things: a) you are a freaking genius. In that case he would have continued excelling in the public school. b) Your teachers gave you straight A's for no reason. This seems more likely to me.
Also: when Emil stopped his country-bragging to ask about safety in Tuuri's home, I thought "wow, he is sensitive! He is clearly an idiot in other ways, but he is social-smart to recognise social cues and their hidden meaning! Wow!"
After telling Mikkel that basically "I'm not sure what you said, but what I understood was lousy" I reconstructed my point of view. He is an idiot in all ways! And I suspect that his own parents may have died, which made him more sensitive to recognise uncertainty and fear in the well-being of others' families... Hense realizing that Tuuri's... interest in safety came from actual experience.
Well, if his parents weren't neglectful, they would notice they were doing a lousy job, wouldn't they?