Thanks for your explanatory note about the boarding school (girls only) in the town of Lycksele. I do appreciate that you, the author, is the God and creator of the reality you are depicting, and in fact, that this reality is entirely fictional. Yes, of course! What else would be the purpose of fiction! Thanks also for the example you give, about the Museum of Gallic History in Paris, that does not in fact exist but makes perfect sense in the book you mentioned. I do agree, you are perfectly eligible to make up material things, characters and events that have no equivalent in the real world.
However, I do ask you to consider that the chances of finding a girls only boarding school in Lycksele are comparable to find that Museum of Gallic History in the middle of the Gobi Desert. Yes, you can make up that one too, of course, there are no limits to what a writer can do, but you will have to deal with the consequences. Your first option is to keep it the way it is, and deal with a readership that doubts your knowledge of your topic. Your second option is to make the school make sense within the plot: there must be reasons for such anomaly: A British knight re-located to the north of Scandinavia and now trying to colonise the region with his educational culture? An abrupt turn in Swedish educational policy? A fantasy novel, where nothing cohers to the real world, and where you can also pick grapes and swim in thermal pools, in the metropolitan centre of Lycksele.
Let’s keep up the dialogue,