Been combing through my notes and I found this little headcanon lists that I never posted. I think it's time for this to enter the light of day.
Mateo is a great singer, that's no secret. But he can also play the guitar and owns one which is kept in his room at their house in Old Avalor Square. He isn't as skilled as Elena, Francisco or Marlena though. However, he is great enough at it that the people who live in Old Avalor ask him to play them a song once or twice during Navidad. Like Marlena, who is the best musician in the city, Mateo grew up in the streets of the Old City Square of Avalor, where despite music being outlawed and banned by Shuriki, families still taught their children in secret of the old ways. Actually, almost everyone in the Old City Square sings beautifully. To this day, the best musicians in the kingdom hail from the nostalgic streets of Old Avalor.
Despite magic and music being outlawed, sports, particularly Olaball, was welcomed and was still celebrated in the kingdom during Shuriki's reign. It was a hard compromise that if not for the hardwork of Esteban, would have never happened. Thus, the sport was taught in most schools across the kingdom and became one of the only things that still brought joy to the people in those dark times.
During Shuriki's reign, english became the official language of the kingdom and every school in Avalor had to teach it to its students. Avalorans had always been great English speakers and most of them already understood the basics of it but Spanish was still the lingua franca amongst many of the citizens. And Shuriki, fearing that they would plan to overthrow her, ordered that English be the only medium of the kingdom. However, families still taught their children Spanish in secret. Mateo and Gabe can speak Spanish fluently, especially Mateo because his grandmother was especially patriotic. Naomi can understand most words but is not as fluent as them, and her knowledge of Spanish is mostly because of the sailors in the port, which means she knows a few mean curses in Spanish.
Naomi, Gabe and Mateo all went to the same high school. Gabe graduated 2 years before Mateo and 3 years before Naomi so he did not see them or interact with them frequently. Mateo and Naomi know of each other because a) they had a few classes together, such as PE and Maruvian languages and b) because both were equally well-known in their respective grades. Naomi because she was transferred in mid-semester of her first year and because a few of the teens her age knew of her father who was the port master. And Mateo because he was well-liked by almost everyone for his kindness and generous patience. He was also the resident bookworm (though he mostly read books on magic but no one knew of course) and quite the scholar, when he actually paid attention. Gabe in school was the typical boy next door, minus being an Olaball player, and everyone practically wanted to be his friend. Anyways, Mateo graduates sometime between season 1 and the first half of season 2, when he has only just turned 17. Naomi graduates at the start of season 3, with flying colors. Both are thrown private parties by Elena and the royal family in the palace to celebrate their graduation.
Naomi has her own room in the palace. It was the guestroom she first used in My Fair Naomi and has since been using whenever her parents are away on business. Elena had it modified to fit her, with permission from the Grand Council, after her first stay there. Funny enough, it is near the guards barracks, though that was just to spite Gabe.
Elena and Mateo's room are on the same wing, whilst Isabel's is on the other side of the palace. Their rooms are actually very near each other, just down the hall from one another and are nearest to the library, though this was just purely coincidental. Nevertheless, it's very convenient in times of need.
Elena frequently visits Mateo's room, ever since he moved into the palace. Firstly, to train, secondly, to check on their enemies, and lastly because she and Flo just like to hang out with Mateo. Whenever there is something on her mind, or if she can't sleep at night, Elena will almost always go to the Royal Wizard's Quarters first. Coincidentally, Elena and Mateo are prone to staying up late because of royal paperwork and practicing magic respectively, and will often run into each other on their way back to their rooms and thus they will proceed to spend time together on their journey back. Because of this, the palace staff have come to associate that if the Crown Princess is not in her room after a long day, then she will have most likely be with her Royal Wizard, either training in the gardens, talking in the library or just working together in mutual silence either in the Grand Council room, the Royal Wizard's Workshop or in the Royal Wizard's Quarters.
The location of Mateo's Workshop is not a secret anymore. This is because Mateo believes that everyone can practice magic freely. After hiding his talents for the better part of his life, Mateo now practices magic in the open for everyone to see. That's why, if he's in the palace, his workshop is always open. He will only close its door if he's out visiting his mother, training with Elena in the gardens, reading or practicing a spell outside, or is in his room. Most of the time, Mateo welcomes any visitor to his workshop with open arms.
It's well-known in the palace that Elena does not tell the best jokes. Or the best puns. Her family and almost everyone who lives in the palace knows this all to well. When she calls out to someone a new joke, they will just grin and bear it because they don't want to upset their crown princess. Mateo is the only one who actually enjoys it because the two of them have the same sense of humor. The two will often tell each other jokes only during training, at first, but this has since increased in frequency since the royal wizard has moved into the palace. And anyone unfortunate enough to be near them can only groan or roll their eyes, but they secretly appreciate that Elena has found such a kindred spirit, even if their puns are so corny.