It makes sense that Elena would have Naomi on her council. For one thing, Naomi is the daughter of two sea captains, who travel a lot. She would naturally pick up some things from the places they visited. This helps her out if she ever has to deal with foreign dignitaries. Two, even though her mother traveled a lot, they still communicated a lot, meaning she still technically has both her parents to raise her into a young woman with a good idea of common sense. She's essentially a jack of all trades to help Elena out with various tasks. This is why she is likely the only non-Royal family member on there, as well as why she has the strongest bond with Elena even though she, Mateo, and Gabe are all her friends. She can always be counted on. As for why Naomi isn't involved with all royal matters, it's again because she has her own matters to attend to with her parents at sea.
This also helps show why she didn't compete for the title of Elena's best friend in "Party Of A Lifetime", yet was shown to be jealous of not possibly being her best friend in "A Spy In The Palace". In the former episode, she was shown in what's pretty much her natural element, a ship out at sea, and knew that getting out was the top priority since they were in a ship that could trap them during a fog . In the latter episode, something personal to her (her worth as a grand counsel member) was in jeopardy of being taken away, and "Finders Leapers" shows that possibly not being seen as needed by the counsel as very hurtful to her.
In "Royal Rivalry" Naomi gets called a kid by Princess Val. What makes this logical or brilliant is the fact that in the past dress length marks the passage of being a woman (usually among the nobility). A dress short to the knee connotes a kid, a young lady to her ankles, and a floor length dress is a woman. Naomi in a knee length dress tells visitors that she still is in fact a child.
"The Adventures In Vallestrella" shorts show Elena being more cautious while Isabel is more adventurous when it's usually the other way around. It makes sense though. "A Gecko's Tale" involved them respectively learning to be more mindful and risk taking. Plus, Isabel has a thirst for knowledge, and would do anything to acquire it. On top of that, Elena is familiar with how Vallestrella is like since the shorts take place after "Realm Of The Jaquins", and would want to make sure Isabel and the baby Jaquins are safe.
The only people that Skylar has ever let ride on him are Elena and Sofia. Since he's royalty himself, it makes sense he'd choose only Royal family members to ride him since they would know how to treat Jaquins, or animals in general, with proper care.
Esteban's arrogance and belief that he knows what's best for Avalor stems from the four decades he spent acting as damage control for Shuriki's negligent and self-centered rule. He spent years as the only one keeping Avalor from falling apart, so it makes sense that he developed such an attitude.
Esteban seems to be prone to being One of the Kids at times despite being in his late fifties to early sixties. Could be excused as trying to keep him relatable to younger viewers, yet other adult characters that are as old as him or slightly younger seem to be more mature than him. Considering Shuriki took over when he was a young adult and he had to step up in his responsibilities without any sort of parental guidance or learning alongside a companion(s), it could be that he Never Grew Up.
Notice that this wasn't an issue in the movie. This can also be chalked up to his family's returned presence having brought the child part of himback out.
During Carla's time as "Rita", Esteban doesn't appear in a single episode. If he did, he'd be a Story-Breaker Power and would've caught the deception very easily. It's more or less established in "King of The Carnaval" that Esteban is not easy to deceive, and he would've immediately recognized Shurki's or even Victor's handiwork. At the very least, he would've noticed Rita's unusual speaking patterns or unusual movements, and Elena would've believed him over Naomi, as the latter was Right for the Wrong Reasons.
So, why didn't Elena talk about her cousin Cristobal as much? To begin with, Cristobal was a lot of fun to be around. Considering the treatment Esteban usually receives, Elena didn't want to hurt his feelings, so she tells Esteban he is her favorite cousin.
Why did the guards on Nueva Vista side against Elena and co. in favor of Shuriki, Cristobal, and the malvagos? In all likelihood, like Cristobal, they were also bribed by Shuriki.
Either that, or these guards are loyalists from her 41-year reign who fled and took refuge in Nueva Vista.
Despite being Shuriki's The Dragon (and Hypercompetent Sidekick) for the past several decades, why does Esteban have no idea who Cristobal, a nobleman and a legitimate candidate to the throne via being King Raul's nephew, is until "Song of the Sirenas"? Shuriki probably kept him Locked Out of the Loop to keep him from getting any ideas (like teaming up with Cristobal to start a rebellion). If Esteban has heard of Cristobal during that period of time, he probably assumed that he was powerless and/or justifiably wary about doing anything about Shuriki.
That would explain why Esteban thought only Elena was fit to take the throne. Otherwise, if he did know about Cristobal beforehand, he would've endorsed him to take the throne sooner instead of Elena due to her age, assuming he was willing to take up the responsibility.
In "First Day of Rule", we learn that Shuriki was making the noblins turn things into gold to make her rich. It doesn't work that way - it would depreciate the gold's value, making it more worthless and should have put Avalor at risk of economic recession. Knowing Shuriki, she probably Didn't Think This Through. Avalor is only successful economically because of Esteban.
On the other hand, it's possible that Esteban, being the voice of reason, stopped her before she could use the gold for money, preventing the economic recession in the first place.
It's also highly likely that this gold was used to bribe people like Cristobal.
For a guy who's spent his whole life Married to the Job (so he's had little experience with women outside of his family besides Shuriki and Paloma, especially since he didn't have his abuela around to educate him on this matter), of course Esteban has pretty awful taste in what women should wear, like Naomi's tacky and ruffled ballroom gown from "My Fair Naomi".
Or, perhaps his bad taste kept him from getting with any women, eh?
When Elena talks about how she'll be spending the Sunflower Festival without her parents for the first time, viewers have noticed that even Carla gives her sympathetic look. As we learn a few episodes later, Carla's mother has been absent from her life for a while (at least a year), so it's possible that Carla related to Elena missing her parents.
Despite being Fish out of Temporal Water, the royal family seem to have adjusted rather well to society despite the possible advancements and changes made in the four decades... though we're not shown any of these possible advancements. It's possible that Avalor remained stagnant in comparison to the rest of the world or just didn't change that much, due to Shuriki's regime. This is can be Truth in Television, due to regimes sometimes being isolationist.
The fact that apparently no other kingdom did anything about Shuriki taking over Avalor might be Truth in Television. Perhaps King Raul had ideas for Avalor that were unpopular or didn't benefit other kingdoms. By the time Elena returns, Avalor is said to be excellent in trade — something that had changed in the past four decades, and Shuriki mocks Elena when she tries to take the throne back, asking "Why ruin a good thing?"
The fact that Shuriki is also a powerful sorceress could also be analogous to how being quick to fighting authoritarian regimes might just result in more bloodshed, which will especially be disapproved by other kingdoms' populace for being a Senseless Sacrifice if it becomes a war of attrition or just doesn't get any major positive results.
It may seem weird that Elena didn't attend Sofia's graduation from Royal Prep, but considering Shuriki was loose at the time, Elena and co. probably believed it was best to stay in Avalor in case Shuriki were to do something while they were abroad.
Migs is shown to be very comforting towards Naomi in "Naomi Knows Best". Considering he's a father to 3 kids, he would know how to interact with kids so that they do what they need to do, yet also wants to make sure they know they're being supported.
It's a good thing King Toshi doesn't put so much stock in seeing his kingdom's traditions replicated. If he did, he probably wouldn't have taken kindly to Esteban making such a mess out of one of Satu's traditional dances. Breaking off the trade agreement would have been the least unfortunate reaction.
On top of that good thing King Toshi was okay with Elena leaving him to help her sister. He could have seen that as she didnt care about an agreement and would rather help her family.
Elena making a paper airplane out of an official document in Sister Time doesnt paint her in the best light either even if it was just for laughs.
Fridge Sadness: Because it's been forty-one years since Shuriki took over and forced the royal family into being sealed away, friends of Elena, Isabel, and their grandparents are either all adults with children (and perhaps even grandchildren) now or dead.
Remember when it was stated that Shuriki forced the Noblins to make gold? Well, we also find out that Cristobal betrayed his family for Shuriki and was being generously compensated with gold for his loyalty, so that means the gold he's been getting was coming from the enslaved Noblins.
Given that Cristobal is the son of the late king's late father, wouldn't that make him next in line for the throne if the royal family is eliminated (or at least if Elena and Isabel are gone; Esteban is not of royalty, so he wouldn't be a possible successor)? Perhaps that's part of why Shuriki bribed him to ensure that he wouldn't start or support a rebellion that would put him in charge.
And with that, who else with ties to the royal family could Shuriki have in her pockets?
Knowing authoritarian regimes and dictatorships in real life, one characteristic of them is that citizens causing trouble, no matter how small the misdemeanor, tend to... "disappear". Who's to say that this didn't happen or could have happened under Shuriki's rule? At least Esteban and Armando are her lieutenants, considering there's at least one shown incident where someone breaking the law is punished rather lightly by Esteban (a boy's flute is confiscated and broken, but neither he or his parents are arrested).
In "Movin' On Up", Rafa offhandedly calls Esteban "horrible". This is probably a jab at him for being arrogant and immature in general (and the fact that she's barely interacted with him, so she probably only knows about these things from people he works with, like Mateo), although it should be reminded that Rafa has lived most of her life under Shuriki's reign (which also personally impacted her, because it caused her father to go on the run) and Esteban was Shuriki's number two. To the public eye, Esteban was probably seen a sellout to the royal family and there are probably still people like Rafa who are suspicious of him.
Since Christmasnote Naomi mentions she celebrates Christmas in "Navidad"/Navidad (in addition to Semana Santa, also known as Holy Week, according to Word of God) are celebrated in Avalor, that would mean Christianity exists in the Ever Realm. Considering Avalor is the Fantasy Counterpart Culture to Latin American countries, which are predominantly Roman Catholic (with other major religious groups being of Christian origin), this makes sense, but this raises the question of what other biblical concepts exist in the Ever Realm.
Given that we learn in the Sofia the First series finale that the Ever Realm takes place in the same world as Neverland and thus is connected to the "real world" via portal, it could be excused as a cultural/religious tradition that was carried over into the Ever Realm.