Studying IB in Norway or Denmark?

My sis wants to study in Norway / Denmark and we have made a few enquiries. She is not from the EU and the schools keep saying she can be offered a place on condition that she holds a residence permit in Norway. Then she needs to apply for a residence permit and prove that she has enough funds etc. Why would she need to apply for a residence permit if she already has one? I am confused.
On the Immigration website for Norway it says she needs to secure a place for school, pay any fees and have 85000 NOK per year in her account - which is all I think we need to do right?
Is anyone from outside the EU studying in Norway or if you know how these things work please let me know.

The school in Denmark says she has to pay boarding fees, which is fine. But they are saying she would only get a permit for one year which is not enough for the IB. Why would she get a permit for one year? Surely people who go there for longer courses stay longer?

Anyone who knows more about this please advise. She prefers those two countries or Sweden and Finland. If you know of any other schools with boarding facilities please let me know.