Ms Li pulled strings to get Kevin good enough grades to pass and stay on the football team....until the very end of his senior year, when if he graduates, she'll, er, the *school* will lose its star athlete and winning record. Suddenly, Kevin's grades drop so much that he has to repeat his senior year. Anyone want to bet his grades rapidly come back up enough for him to regain his eligibility?
Keeping Kevin at all costs is totally justified. The last time he stopped playing the whole town was labelled "a loser town" and a full blown collapse of property values ensued!
The Morgendorffers are originally from Texas, as Beavis And Butthead was based there. It is very easy to imagine Daria being tormented there and developing her anti-social personality which she brought to Lawndale, even though everyone there pretty much lets her do her thing.
Tiffany turns up to the mother/daughter fashion show having asked for the prettiest model from a modelling agency. They send a very tall and thin black model - to play her mother. We're supposed to work out that this is an unvoiced, unofficial cameo by Naomi Campbell.
Little Sister, the song Trent wrote for Jane's birthday, shows their shared disdain for mainstream society in Trent's typical unsubtle way, but the repeated 'does anybody know why we're here' line, clumsy as it is, doesn't sound like something Trent would say. It sounds more like... ohhh.
Quinn's behavior towards boys is a misunderstanding of her parents' relationship. She sees her mother walking all over her father and interprets this as the man is used by the woman for what he can give her i.e. money, stuff, etc. The misunderstanding is that she doesn't see the other layers of Jake and Helen's relationship, wherein they are ideologically aligned, comforting and nurturing of each other, and obviously enjoy their physical relationship. In her time with David the tutor, she finally encounters a male of her age bracket that isn't immediately seduced by her looks and from then on begins to look for deeper relationships with boys i.e. looking for a real boyfriend instead of just eye candy who buys her stuff.
The episode "Boxing Daria" shows Quinn desperately trying to get her parents attention while they are worrying over Daria's unwillingness to be friendly with others. That may reveal another strong reason why Quinn neglects her education in favor of popularity: competing with Daria academically is futile because Daria would likely always overshadow her in grades and academic achievements, but popularity is the one thing Quinn can do better than Daria.
From The Daria Database: Quinn's Baby-sitting Spreadsheet makes note of Todd Green, age 8, who pestered Quinn to play games until she tricked him into Hide and Seek so she could watch a movie. Ha ha, typical Quinn right? Until you realize this neglected child, whom according to Quinn "walks funny and has a really round head" might actually be disabled.
Brittany's little brother is a Chronic Pet Killer, considering the fact that he is apparently the reason they don't name their pets anymore. In which case, what got him like that in the first place?
The help Lawndale High offers to troubled students are thinly-veiled attempts to enforce conformity, single out the outcasts, and force-feed them school spirit. It serves more to the staff's interests than the students'. But there probably are students in the school who really need help but are getting ignored because they don't fit the staff's ideas of how a depressed teen would look and act.