Was just watching old re-runs on Youtube of this awesome show... types anyone?
Daria: I really like her goals to become a writer, and we have a similiar-ish personality. At first she seems very Fi-ish due to her lack of expressive emotions, but I view Fe manifesting a lot differently depending on the specific type, and there's always a certain sense of collectivism/humanitarianism to her views that makes me think she's Fe-valuing.... especially her secret childhood love for sappy things. LII perhaps?
Quinn: I would say Daria's conflictor, SEE. She's the life of the party, very popular/outgoing, knows how to be charismatic with people, and it's all dolled out with that sheer Gamma toughness. Her Se-valuing is so evident as she constantly barbs on people without worrying about the comfort or tact at all. The show seems very anti-Gamma so she is the frequent butt of the jokes more often than not.
Daria's mom: I'm not very confident in this one but: ESE? Yes, I would believe Daria's mom is actually her dual. When all the chips are down, when she feels weak/unprotected & lost the most, Daria tries to call on her mommy for help. This might seem well, typical (it's her mom, duh)... but she relies on emotional, private stuff to be worked out with her. Daria's mom is a workaholic like a lot of ESEs, but it's always done in a way where it doesn't seem to hit Daria's polr. She can still get upset at her mom, but they share similiar views and both don't really like Quinn's shallowness.
Daria's dad: I'm stuck on either EII or LII... but based on their shaky marriage (it was a cartoon played up for drama I know, but taken seriously for criticism purposes, their relationship really was genuinely dysfunctional) and lack of any respectful feelings... I'd say he's a very, very unhealthy EII.
Trent: IEI. Typical romantic/slacker vibe, don't see him as anything else. Has sooooo much trouble exerting himself. Beta epicness and awe at the crazy shit of the world. Has such an underlying erotic vibe that makes him easy to fall in love with, but so hard to work with/be dependent on. Te-polr is so crystal clear, can't think of anything else.
Tom: Delta IEE or Alpha ILE most likely. Has a very down to earth yet diplomatic & idealistic brain all at once, looks like he'd complement Daria's writing well by being more of a refined/public voice for her works. Always dresses neat, is wealthy, but doesn't come across as smug or pretentious about it. Looks like he'd fit into any college/aristocratic setting extremely well.
Brittany: Despite being brain-dead she has a great moral character... and does surprisingly heroic things for, well, a Cheerleader. Again she secretly always seems to be there for Daria when she needs it the most (and vice-versa) which is what duals do, so I'm guessing another ESE just not a kinda more ... obvious one? like Daria's mother. (Brittany's boyfriend Kevin is obviously not her dual, I don't think- I say he's SLE.) There would be lots of chemistry between Kevin and Trent I'd imagine.
That black dude on campus: SEI or IEE.
That black girl that tries too hard to be goody-goody & perfect: A much more healthy EII?
Mr. O'Neil: He's such a caricature and comic-relief & they ALWAYS make fun of him (well they do the others but almost every character has redeeming moments but his over-the-top emotional sentimentality is always ripped on) so I don't really know. He's too much of a joke to type effectively, perhaps.
Weird bugging eye-out teacher (forgot name): LSI? Come to think of it, I could actually see a duality between him and Mr. O'Neil (so EIE for o'neil?).