Airk and Kit had the same upbringing and education. Which was probably a lot less strict than you would expect of a hereditary monarchy, but unsurprising, given their parents were not hereditary monarchs. Airk was cutting gym class, but their academic curriculum wasn't mentioned. I doubt either was a model student when it came to subjects they didn't enjoy.
I suppose so, but I can't imagine the people of Tir Asleen having a whole lot of faith in Airk as a ruler.
It seemed to be common knowledge that he could most often be found lazing about or womanizing. In contrast, his sister was seen as mostly stable... or at least stable enough that she could help join two kingdoms and serve as a figurehead until the return of Elora Danan.
I can't imagine that much more faith in the idea of a King Airk would be inspired among the general populous (rather than in Kit) after he was taken and she returns home as one of the heroes who saved him.