001948 Gives us our first mention of Betty Crocker, who is certainly the opposite of a dropped element. Even from the beginning John is on to her ‘plot’ and calls her his arch-nemesis.
Frankly my personal opinion is this is a bit of retroactive foreshadowing. What started out as a mere hyperbolic description of John’s cake-hate turned into a long lasting antagonist.
There is a link on this page to the Betty Crocker wikipedia article, which as of 2016 now mentions homestuck.
001949 John examines his father’s harlequin statues in the livingroom, which he hates. This will be dramatically ironic later, as well as make up another element of a primary antagonist.