The use of Beethoven's Fifth in the intro uses the motif of V-5: it comes when it features all five Catarinas in a V formation. Beethoven's Fifth is referred to as the Victory song, note partly because the famous duh-duh-duh-DUH resembles the morse code for the letter V - V for victory! and the Catarina Council was formed to find a way to victory in the otome game (though for Catarina victory is less for winning and just surviving destruction).
The child-teen transitions with Catarina and her friends are symbolic of her relationships with them.
With Geordo, her fiancé, both child and teen scenes are formal dancing, which ends with Catarina doing something boisterous, which shows how little she cares for the arrangement and how Geordo is serious about his engagement.
With Keith, they are riding piggy-back style in both scenes, showing their sibling-closeness. As children, Catarina is carrying Keith, which is indicative of her plans to be a big sister to him. As teens, Keith is the one carrying Catarina, as he has been indulging her silly behavior for years.
Child Catarina and Mary are shown in a garden, with Mary crying as she runs towards the latter and transitions into teen Catarina and Mary dance for a moment. Not only it shows Mary's Character Development from sad and timid girl enduring abuse from her older half-sisters to a happy and confident lady who takes no crap from anyone thanks to her relationship with Catarina, it is worth noting because she is the only person other than Geordo that Catarina is shown dancing with, which hints at Mary's aggressive romantic pursuit on par with the third prince.
With Alan, Catarina is swinging from a tree's branches because she befriended him in tree-climbing duels, and then teenager Catarina drops into teenager Alan's arms, which hints at the rivalry becoming romantic.
With Nicol, both scenes are silent and still. The only motion is Nicol's dazzling smile and Catarina's swoon. This hints at Nicol keeping his distance from Catarina despite their mutual attraction.
With Sophia, child Catarina is sitting on a couch and child-Sophia scoots close to her so they can read together. As teenagers, they are still reading together, because their love of romance-novels transcends lifetimes.
Teenager Catarina is, of course, eating a cake with (Sweet) Maria, the Supreme Chef. And it's obvious that Catarina and Maria only met in their teenage years so unlike the examples above, this segment only depicts them on their teenage forms.
Catarina being dense to all the interests of her Harem makes sense when considering her original goal of avoiding her Doom Endings. Since she's so focused on trying not to die and just staying alive, she achieved tunnel vision that prevents her from seeing the positive changes in the people around her. She keeps thinking she is still a villainess when really, her being a kinder and better person than the game-Catarina has actively prevented any of the original endings of the game. It is also why she keeps thinking everyone likes Maria more than herself, because the original Catarina was a giant Hate Sink and Maria had Chronic Hero Syndrome thanks to being an otome game protagonist.
It is because of this tunnel vision that makes it difficult for Catarina to see the Butterfly Effect that has already happened in the setting. Thanks to the In Spite of a Nail events that still happen in the school, Catarina's tunnel vision makes her think the game is still playing out. Geordo, Alan, Keith, and Nicol all meet Maria as they do in the game, taking an interest in her, but Catarina's still focused on her own goals of watching over Maria that she doesn't realize the specific interest in Maria (not to mention the context of the meetings) has already changed because of Catarina's influence.
This tunnel vision can also account for why Catarina was so confused at Maria's backstory and "Sirius"/Raphael turning out to be a villain in addition of the existence of dark magic because she never saw these events play out in the original Fortune Lover game. The game never explained said events or the monkey girl just didn't get to that part of the game before she died, so it's understandable to see Catarina be thrown off because the Butterfly Effect is in full motion now that the game is real life. In her former life, she only played and completed Keith, Alan, and Geordo's routes.
Despite all the participants in the harem (sans Geordo) doing their best to woo Catarina, they aren't saying their feelings outright, which makes sense in context when it becomes plain that all of them know Catarina is painfully Oblivious to Love. She sees everyone through the Power of Friendship, so for someone to try breaking it with an outright confession could lead to trouble. Not to mention how Fortune Lover takes place in a medieval society, so someone trying to woo another person's fiance could lead to public scandal. Fortunately for the rivals, Catarina being Oblivious to Love means that Geordo doesn't make any progress at all either.
Back at Episode 1, shortly after Catarina's accident, Anne is overjoyed when her mistress finally gets engaged to Geordo. Alongside her and Geordo's shared shock and distress when Catarina claims that her scar wasn't a big deal when it is, her sudden bouts of emotion is justified considering her history. Anne was abandoned by her father shortly after she was burnt at a house fire that killed her mother, deeming her as useless in political marriages. Catarina getting engaged to not just a noble, but a member of the royalty who is already intrigued over her sudden change of personality and also doesn't care about the scar on her head, is quite a big deal to Anne and she can't help but be happy about it.
In Fortune Lover, the protagonist of the game is Maria Campbell, as in the main character or MC.
Maria's backstory is Harsher in Hindsight when it comes to the original game, because in the end, she only is able to achieve one person's attention per route compared to this new timeline. Her desire was for someone to look at her, and depending on the route, she would achieve that, but at the cost of game-Catarina and so many others bullying her for things outside of her control. Thankfully, with the monkey girl being Catarina, this entire situation is Heartwarming in Hindsight because Catarina already helped everyone out, letting Maria be a normal student in a clique of friends which, by the way, consists of nobles from the higher class, and they all have their fair share of influence on the student body, preventing the original game's bullying. The cherry on top is how every member of said group doesn't judge her for being a commoner and instead appreciates her for her hard work, dedication, and her kindhearted nature. Why would Maria fall in love with the four main leads when Catarina gave her everything she wanted in friends and for someone to recognize her, more so than the original game?
In the game, Maria is supposed to fall to one of the romanceable male characters (Geordo, Alan, Keith, Nicol). But in this story, all of them fall for Catarina instead. True to a common visual novel trope, this unlocked a secret route where the heroine (Maria) doesn't fall to any of the male leads and revealed the fifth male character story (Sirius/Raphael).
In Episode 7, Sophia's agreeing Mary's sentiment of willing to eat poison if Catarina wants her to may seem to be continuing a gag about Mary's clinginess towards Catarina, but earlier that episode Sophia dreamed of Atsuko's grief towards the Monkey Girl's death, and throughout the episode, Sophia has been interpreting that dream to be about herself and Catarina. So what she really means was she's seeking Reincarnation Friendship with Catarina, just like what Atsuko did.
In Fortune Lover, there is no guarantee that Maria will get Happy Ever After with her chosen love interest, regardless of whether she will go for the good end or the bad end of her chosen route. It is because that her Parental Abandonment issues being left unaddressed and the social isolation that she endured back in the game will get worse than what she endured before she entered into a relationship with her chosen Love Interest (a commoner marrying a noble, being responsible of breaking an engagement, and/or being the one who is responsible for the exile/death of a member of a ducal house are the tips of the iceberg). Since it's an Otome Game, it's all about Maria saving the Love Interests from their predicaments, not the reverse. In the series however, the game becomes real and thus greatly expands and fills in the gaps that Fortune Lover left behind. This enables Catarina, who despite her own issues, is overall a well-adjusted individual, manages to learn more about Maria and addresses her issues: giving her friendship, protecting her from her bullies and telling them that everything she achieves is because she works hard to get there, and indirectly giving Maria's mother a wake-up call that she must fix her relationship with her daughter before it's too late.
Geordo mentions in the tenth episode that dark magic amplifies already existing feelings of jealousy and envy. This creates a Harsher in Hindsight in Fortune Lover regards to Catarina's bullying of Maria, particularly the Keith and Geordo routes' bad endings when Catarina tries to murder Maria. The Asshole Victim (Catarina) is merely a catspaw and scapegoat for the hidden route's character (Sirius/Raphael) disposing of the oneperson (Maria) who can see his power. With Maria out of the picture, he keeps hidden amongst the peerage, continuing his plan to destroy every last member of the nobility that will surely cause discord to the kingdom. And killing a member of a ducal house and the exile of her murderer are perfect starting points for his plans.
In chapter 31 of the manga, Catarina spent some minutes thinking about a conspiracy before she has to stop and ask for food... because her body is low on energy. With this revelation, one can't help but wonder if she has high metabolism or worse, diabetes.
Even at the beginning of the novel, Geordo explains why he engaged the "old" Catarina despite he absolutely loathes her, and it's all political calculations—he doesn't want to get involved in the struggles between Geoffrey, Ian, and/or their supporters, and Duke Luigi happens to be neutral in this. The scar thing is just a good excuse to tell others. This all comes from an eight-year-old boy. While Geordo is undeniably a genius that can help him navigate the court and political intrigue, without Catarina's intervention from the main series or letting the course that will lead to the events of Fortune Lover unfold, he will grow up as an emotionally-underdeveloped Manchild.
And this also shows that despite Geoffrey loving his younger brothers, especially his younger twin brothers, even he doesn't know that neither Geordo nor Alan want the Crown, showing that even with all of his claims that he cares for his younger siblings, he doesn't even know a thing or two about them. In the distorted timeline, Geordo is more than willing to throw his claim just to be with Catarina, while Alan has little to no interest to the mess as well. And in the unaltered timeline, he doesn't have an idea that both twins are at odds with one another.