Loose Threads:

Is that big bottle of silver nitrate in the kitchen the same one Penny was drinking out of?

What is Trent doing up at 7:30 in the morning?

Notables:

The title is a reference to Les Miserables, which is a play about the French Revolution.

Helen is very proud of herself for actually being home for a family dinner, and doesn't like it when no one really notices.

The Lanes have a telescope downstairs near the door, but we've never seen any of them use it.

Penny is carrying her bird in a cat-carrier. This has got to be symbolic in a square-peg-in-a-round-hole way.

Jane's comment about the manger is a biblical reference. When Mary and Joseph are in Bethleham looking for an Inn, they can't find anywhere else to stay.

Trent's breaking guitar string may be symbolic for the breaking of his family ties. His comment about sharpening his pick may mean he's planning on cutting a few more himself.

Quinn's milk-carton reading/comment about chewing the cud may be another biblical reference (only because there's a couple in this ep), as there's some strange passage about animals (including rabbits) that chew cud, but it's more likely a reference to "chewing the fat", which is slang for gossiping, which Quinn certainly has done a lot of.

Daria's Scrabble letters being "TNT" is probably a reference to dynamite, and a foreshadowing of an explosion to come (probably the destruction of Daria's crush on Trent).

Quinn may be an anime fan: at least, she's got a picture on her wall of a masked girl with long, spiky blue hair.

Daria's comment to Quinn about "pearl drops of wisdom" is a parody of an old phrase "pearls of wisdom." Daria added the drops, which seems to be a reference to gumdrops, thereby slightly changing the meaning of the phrase.
Pearl Drops is also an extremely gritty whitening toothpaste.

One of Jane's paintings is on the wall over the couch in Daria's daydream sequence.

Jane's comment about the "Wandering Lanes" is a reference to the Wandering Jew, supposedly a Jew who mocked Jesus on his way to the cross and was condemned to wander on earth until Judgment Day.

Mistakes:

Unless Helen is serving while Daria makes her comment about the library, there shouldn't be a missing square from the lasagna pan, and it's cut differently in the later scene than the earlier ones (3x3 vs 2x3)

Trent manages to break a guitar string, but his guitar doesn't really sound any different.

Double Meanings:

None yet.