Holy moley are there finally answers. I have been so devastatingly wrong about everything even though it was literally in my face. But Oki, I said to myself, I’m sure there are a lot of cute blond 
girls in the entire Dowa Kingdom! But Oki, I said again, the Prince clearly loves Lotta! Bah, I say to you! Bah, past Oki! In truth the spoiler reveal of this episode, which is coming posthence so look away should you desire not to have your mind cast upon this truth, is that Lotta and Jean are both royalty. Nay indeed, not only are they royalty but Jean is the true successor of the Kingdom! So in short, holy shit. I lost my mind in this episode when the truth was revealed. Imagine my casual acceptance of the status quo. You see this episode featured largely what we are used to for this show: many many sweets which endeavor to make me gain weight and indulge in delicious decadence. Jean being oblivious and in turn, we the viewer being oblivious, and so we remained until this day.
But now it all makes sense. Why the King is pretty chill about being around Lotta and, in this episode quite especially, Jean. It could even explain why the King didn’t step down- he is expecting Jean to be revealed as a true successor. It explains the nature of a sweet tooth that is passed down in the family, why Grossular has Jean monitored by Nino, and why Prince Schwan would want to look into Lotta at the sight of her. As it stands the second Princess went missing overboard with her silver haired guard 33 years ago- and has been presumed every since. Meanwhile we learn that Nino has known this whole truth and even, as it is heavily implied, has been told it all by Grossular.
So did the Princess, their true mother, marry a commoner and change her name? Is Grossular really their father? Holy shit what if Grossular is their father?
Does that mean Lilium is actually the evil one and he’s working with Schwan? Will Mauve totally marry Jean if he is going to be King? Holy shit. I am losing it at this episode because I just did not expect it for him to be the next in line. Just cute subtleties like Lotta loving sweets in the same way the King does and the entire political atmosphere of this episode have me wondering what the rest of the series will be? If anything, I expect a total meltdown and absolute shitfit from Schwan and a revelation from somewhere.
But Jean is really the crown prince. . .hot damn.
Oki
Keep in mind Nino reports to someone else besides Grossular, I’m guessing the king himself or one of his close aides.
My guess is the princess faked death in the ship accident, started living as a commoner under the Otus name, then died for real at the train accident that was mentioned in episode 6 and which Grossular later had to solve. Maybe the guard who disappeared with the princess is Jean’s father? Or Grossular’s relative? Or both?
Another theory I have is Nino being the son of the silver haired guard, thus why he was tasked to look after Jean. Or depending on his age (he must be older than Jean for sure) and if he used dye on his hair, he may be the guard himself.