At first, it may seem kind of out-of-the-blue that Kim can play the piano. But then it hits you: Kam's her brother; she's bound to have learned something living with the class' pianist!
Big D is known to sell Extreme Ham. What else would you call that? Deviled ham!
Phil's goggles serving as his glasses makes sense; as he's used to having his inventions explode, it's more than likely he decided to combine his vision aids with something a bit more protective than standard eyeglasses or contact lenses.
The kids that bring up Li'l D's off-episode mishaps in the Christmas Episode are Philly Phil, Kim, and Kam. While this may seem random, there's actually some level of reasoning.
"The white-water rafting incident at Westley": Brought up by Phil. As someone who dabbles with water-sensitive gadgets, of course he's going to be a little pissed off.
"The thing at the zoo": Brought up by Kim. Animal fur and/or print is a common motif in fashion.
"The ice cream sundae debacle at Sunny's": Brought up by Kam. Given that Kam is the most academic-oriented of the kids, he's obviously going to be concerned about something potentially impacting his grades.
Kim and Kam share a lot of things, including their voice actor.
While Kim remains mostly a Nice Girl throughout the series, Kam becomes more rude and sarcastic as the series goes on, culminating in him grabbing the Jerkass Ball in the Christmas Episode. Given his tendency to be ignored, of course he's going to lash out.
The kids' instrument choices reflect their personalities/roles.
Li'l D (Drums): Drums are very loud and noticeable, but are also responsible for keeping the beat. Li'l D may be a Bratty Half-Pint, but he's not the leader for nothing.
Eddie (Wind instruments): Clarinets, trumpets, and the like are often associated with high class, and Eddie is the Token Rich Student.
Kim (Percussion and turntables): DJs constantly change music like the world of fashion. Her also being a percussionist also distinguishes her from her brother.
Kam (Piano): Pianos are often associated with classical music, Kam's preferred genre. Pianists are also often forgotten, fitting his role as the No-Respect Guy.
Philly Phil (Bass): Nobody Loves the Bassist is a trope for a reason, matching Phil's unpopularity at school. Basses also often carry the beat of a song, and the class more or less loses motivation when he briefly leaves.
Tamika (Harp, guitar, and other stringed instruments): These instruments are often the most prominent in a song, matching Tamika's brash nature. They can be used in both harsh and soft pieces, matching both her external brashness and hidden gentleness.
Madison (Violin and cello): These instruments are usually considered to be light-hearted, and Madison is The Heart of the class.
The kids display a lack of wisdom quite often. While the Rule of Funny is certainly in effect, they're also kids, more specifically aged 12/13; they simply don't have the wisdom that comes from age.
Why are the kids' personalities different in the earlier episodes? They likely don't know each other as well and being 12-13, hide some aspects of their personalities to fit in better. Their later episode personalities are the result of them feeling more comfortable with each other and thus being more willing to show their true colors.
Only Madison looks her actual age. Tamika and Phil both look older, while Li'l D, Eddie, Kim, and Kam all look younger. Kids do grow up at different rates after all.
The kids (sans Eddie) get reassigned personalities by Cheddar Man as part of being "pop stars" in "Am I Blue?" While the reshuffle may seem random, there's actually some logic in their new roles (minus Tamika, who seems to have been assigned the leftover).
Madison: Smart. While not conventionally smart in the slightest, she's in fact very perceptive and good at picking up clues/hints her classmates tend to miss. She also tends to blurt out the obvious solutions.
Kam: Sassy. As he's already a Deadpan Snarker, this role is almost a perfect slide in.
Li'l D and Philly Phil: Twins. Being Heterosexual Life-Partners, they're already close. It's also implied Philly Phil thinks of Li'l D as his best/most trusted friend.
Kim: Rich. She's The Fashionista of the group, and fashion can be a very lucrative career. A large bank account also goes a long way in helping buy fashionable clothes.
Despite Sunny's training in "Westley Side Story," the kids (minus the currently-absent Kim and Kam) seemingly still can't speak in sync. Li'l D finishes the line first, and Eddie finishes the line last. Except three of them can- Madison, Philly Phil, and Tamika, the three string players.
The kids' Limited Social Circles may be justified by them constantly causing some sort of trouble at Westley. The other students, including the other first-years, likely don't want to associate with them.
Why is Eddie the only one to not get turned blue in "Am I Blue?" Not only is he the only main kid to not have any kind of blue on his outfit (Li'l D's pants, Madison's capris, Phil's goggles and part of his socks, most of Tamika's outfit, Kam's pants and part of his tie, and Kim's backpack and most of her skirt), he's already associated with the blues via "A Richer Shade of Blue."
Why is Kam the one to point out that it doesn't make sense for BROC to be able to reject Phil since Phil made him? Well, as is shown in "Kam Inc.", Kam has a decent amount of tech skills so he's probably bewildered by BROC being able to break his programming.
Westley School is terrifying when you think about it. Between chronic underfunding and what they serve in the cafeteria, it's a wonder anyone would send their kid there.
Tying into that, one has to wonder as to how the school hasn't been shut down.
The sheer fact that Westley allowed for someone with criminal potential like Mr. Gone to be hired is pretty terrifying.
Philly Phil is shown to be able to eat and even enjoy the food served at Westley, and even other unusual items, like a pinecone with mud on it, a donut with a lit candle, and a soda can (to be fair, he does seem to have trouble with the last one). That can't be good for his digestive system...
Well, given that he's done a lot of scientific experiments, this could double as Fridge Brilliance, as he's probably made himself tolerant of the effects, however, that does beg the question as to how many tries it took before he got immune.
Phil has also been known to take part in life-endangering experiments, and in "Big Robot on Campus," he has zero hesitations about climbing onto a single-seat biplane with just his bare hands to hold himself. Combined with his severe self-esteem issues, just how much does he actually value his own life?
In "Big Robot on Campus," Philly Phil builds a robot, BROC, intending to become popular by associating with BROC. When BROC becomes popular but Phil doesn't, Phil says "BROC says I'm crowdin' his style." Kam points out that Phil made BROC, so the robot shouldn't have the right to say that. Phil's response? A shrug. The implication is that he's USED to being treated like this.
A minor example, but it's still there. The Renaissance Fair in "Safety Last" features a "Plague Re-enactment" tent. Granted, you don't actually see it and it's never mentioned again, but still...
Man's Voice: This plague is so realistic!
Man's Voice 2: What a rash!
Woman's Voice: Oh- I can't feel my legs!
The kids are all described as misfits or outcasts. While this makes sense for characters like Eddie or Philly Phil, that this even applies to Kim and Tamika begs the question of if this is a normal first-year thing or if they're just that unpopular for whatever reason.
Well, Kam fits the role of social outcast/misfit with his genuine enthusiasm for education and learning as well as his stick-in-the-mud nature so Kim's outcast status can probably be explained by her standing by her brother instead of ditching him to get in with the popular crowd.
Everything about Soul Stack Records is creepy. There's the obvious dehumanizing metaphor for how the music industry treats its star talent, but goofy cartoony stuff aside the industry really does tear their stars down. Metaphors for the music industry aside, the place is Hell.
That nobody really reacts to the obvious supernatural elements that strongly suggests this might be normal in this universe.
