In "Parent Death Trap", the cat Churchill, is named after the cat from "Pet Semetary".
The name of the dad in Parent Death trap is Archibald and that is the same as one of the middle names of the actor who plays him: Shaughnessy Archibald Ronald Redden.
The Grantham Family Ashtray makes its most blatant appearance of the series to date in The Parent Death Trap when Lyle picks it up at the grocery store, examines it briefly, then puts it back on a shelf.
At the end of the episode as the comic pages flip each page shows an illustration of a previous episode. This time the eps are: Mums (3.1A), Skincrawlers (1.6A), and Night of the Paw (1.5A).
In To Grandmother's House We Go the Grantham Family Ashtray is on Marcia's bedside table.