Thank you for your answer :) You are wrong Actually is not about her knowledge of Fractals that i do know that her Intelligence and love of learning is outstanding in Elsa again look at this "official Canon image" of one of frozen Disney stories where she clearly loves to learn about Geometry media.tumblr.com/10d4365a99b9e… Geometry is used a lot in architecture and construction, as knowing what shapes to use plays an important role in making sure a building is structurally sound. The very first thing Elsa does when making her castle is creating a center point to ensure the structure will be balanced. and to be honest to build a castle of ice of that size with so many details and also the bridge it requires a brilliant and with deep knowledge in both Architecture and engineering and not as you say that any person with some knowledge would built thse structures.
About Acceptance. you are also wrong.. after so many years of self denial and brainwashing (Her parents telling her what to do) is really Outstanding that this trait saw the light after she escape to the mountain. if this was a trait that was just a secondary trait, it would probably never saw the light of the day.
About Individuality: the same reason as acceptance.
About self -preservation actually , Hiding to protect other people is actually a selfless act, quite the opposite of self- preservation and also remember that some parts of her self- preservation are not actually hers but put into her mind by her parents (Brainwash, conceal dont feel) is that so that you dont actually see any signs of self preservation in Frozen fever.
Is not that she has some Ravenclaw traits.. actually she has them all (Intelligence, Wit, Wisdom, Creativity,Originality, Individuality and Acceptance). In the other hand she only has three (3) Slytherin traits Resourcefulness, Self-Preservation, Determination while she lacks Traditionalism, Cunning, Ambition, Leadership qualities, Cleverness, Fraternity, desire for Power.
And about the Sorting hat. it would choose Ravenclaw because that is the house where Elsa can learn to be herself , satisfy her thirst for knowledge and accept to be "Different" as the Ravenclaw welcome letter say "Another cool thing about Ravenclaw is that our people are the most individual – some might even call them eccentrics. But geniuses are often out of step with ordinary folk, and unlike some other houses we could mention, we think you’ve got the right to wear what you like, believe what you want, and say what you feel. We aren’t put off by people who march to a different tune; on the contrary, we value them!"
contrary to Slytherin that not only Elsa lacks the two (2) traits that Salazar Slytherin values the most in his students (Ambition and Cunning) and as the Slytherin welcome letter say "Slytherin will help you on the way to greatness and be part of the elite" thats not what Elsa is looking for