Loose Threads:

Does Kevin ever figure out about Brittany's two-timing?

Why are taxi cabs lining up in front of a grunge club?

Why did Mr. O'Neill's talk about King Lear trigger a rash?

Notables:

Lawndale has some fast-food burger joint called Cluster Burger.

The emergency exit alarm doesn't work.

The clock on the wall in Mr. O'Neill's class either reads 4:05 (which should be after school) or 1:20.

Quinn knows where Daria keeps all her stuff.

The Sick, Sad World homicidal houseplants bit may be a reference to "Little Shop of Horrors", which also involves a doctor (of sorts; a dentist) and a love story. Oh, and a man-eating plant.

Daria plays Gin Rummy.

Mistakes:

Rashes don't advance that fast. This was probably done for time/dramatic purposes, but it's still wrong.

Daria reads the heading "10 warning signs" but only answers seven.

Double Meanings:

None yet.