Loose Threads:

None yet.

Notables:

The title is a reference to cards, specifically the Jack of Hearts. This is interesting, as it may be a reference to his standing in the family, perhaps with Helen as King (and ruler), Quinn as Queen (certainly drama, and it's what her name means) and Daria probably as Ace (trump them all).
It may also be a reference to "Write Where it Hurts," in which Jake, Helen, Quinn, and Daria sit down for a game of hearts at Jake's request.

Jane is probably a Punch and Judy fan.

Lawndale does have hidden cameras and bomb-sniffing dogs.

Daria's comment about Marconi is a reference to Gugliermo Marconi, "Father of Radio".

Daria's comment "Dr. Quinn, Medicine Moron" is a reference to a TV show titled "Dr. Quinn, Medicine Woman."

Daria's comment about bionic limbs is a reference to an old TV show, The Six Million Dollar man.

The Morgendorffer's having Operation was mentioned in "The Big House." Quinn apparently doesn't play much.

Ruth mentions "children." Apparently Jake has at least one sibling we've never met.

Jake's running into the yard and shouting "Merry Christmas you little old garden gnome" was probably a reference to A Christmas Carol, by Charles Dickens.
It may instead be a reference to "It's a Wonderful Life", when George goes running through Bedford Falls yelling "Merry Christmas" to the various buildings and people after realizing how truly wonderful his life is.

Mistakes:

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Double Meanings:

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