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Leah is related to the royal family of Cornia.
The mark of the Cornian Royal Family seems to be their blue hair. Leah is the only other character in the game to share that trait - albeit it is a much darker shade of it. But it should also be noted that, while Ilenia shares her father's hair color, Alain is a bit darker than that, so it could be a case of Patchwork Kids. Maybe it was a banished branch of the family, who decided she would be safer with Cornia's then mortal enemy?King Gerard had plenty of consorts.
Queen Ilenia must have had siblings so that Virgina could be her niece, and Gerard died while she was still a child (though we're never told how old was she then). It seems unlikely that Gerard himself had siblings, since the throne went back to his parents after his death. This means that, either Ilenia's siblings weren't worth mentioning, or they weren't born yet by the time of Gerard's untimely death.The Bunny Bestrals are just wererats in disguise.
The Fevrith Archive makes no mention of the Bunny Bestrals, which is odd, since other non-playable bloodlines are featured in it. However, it does take the time to mention the Rat Bestrals, which the only representative of them being Elgor. But, what if the wererats actively employed the Rule of Cute to make ends meet by dressing up as bunnies? And the other Bestrals just turn a blind eye to them, pretending to be fooled?- Until 1912, Rabbits and Hares were classified in the Order Rodentia, having been considered to be related to rodents like mice... and Rats. Since the Archive is, in the tutorial, outright stated to be something Josef compiles in-universe for Alain to reference, it wouldn't be unusual for his information to be either out of date or incomplete, and Bastorias was noted to mostly keep to itself before the war. It could also well be that before Zenoira's invasion, the Bunny Bestrals were trying to be recognized as separate from Rat Bestrals, but the war gave them all different priorities. In that scenario, since the Archive is likely something Alain references to make sure he doesn't make any faux pas (which for a king, could have major consequences), Josef could have excluded Bunny Bestrals altogether while noting Rat Bestrals are rarely seen, as a way of politically recognizing their differences without openly stating it. For an example in real life, think of how many major nations cannot openly recognize Taiwan as a separate entity from China, lest they face consequences such as trade restrictions, but nonetheless, said nations treat Taiwan as independent.
Alcina is the reason why it took Zenoira so long to locate Scarlett.
Alcina herself states that she shielded Alain's presence on Palevia from Zenoiran eyes. What if that accidently also included other people on the isle, including Scarlett? That would make Alcina one of the biggest meddlers of inner Zenoira.