I also used the word 'esprit' for familiars in my WIP! I guess it is a common word to come up with. Anyway, my first feedback on this site hope it's OK.
I liked the writing, it was colorful and vivid. I enjoyed the relationship between brother and sister and I love friendly big guy characters like Cornias. Reading how the dreams work was also interesting.
Improvement wise...
Dreams are probably difficult to make concrete, perhaps grounding the readers with more detail in one aspect, such as the main character or the setting might help some? I think you also have a fair bit of repetitive exposition, for example, the explanations about the dreams during the fight, and also drawing the readers attention to Sophie's grace and zeal on at least two or more occasions. I found the tension on and off. Cutting some exposition and better phrasing some character actions or descriptions such as yawning and childish dreams etc might help with that.
My skimmed page three, as I felt there wasn't much going on other than a blow by blow account, and on page 7 I was confused about the silver bar until Sophie's thought popped up. I wasn't quite sure what kind of bar? What it looked like? How he climbed through it?
That sentence did seem almost like head hopping. She can't know what he is thinking, and you've made it seem like she's guessing, but it's a pretty exact assumption and is also mirrors the POV thought right before it. You can probably cut that.
I hope this was useful. All in all, I liked this piece and would read more. If you don't mind me asking, what kind of audience/age group you are writing for? I wasn't quite sure if it was Children's or YA or Adult Fantasy