An episode which comes later than "All Hallows' Eve", "Monster Smurfs", would have an observance day similar to Halloween called Spook-A-Smurf Eve for the Smurfs to celebrate, probably due to Jokey's birthday being on Halloween.
"All Hallows' Eve" establishes the birthdays of both Jokey and Gargamel being on Halloween. Due to this occasion, there are two callbacks to the first season focused on them respectively: The first scene featuring Smurf Village is a callback to the beginning of "Jokey's Medicine", with Greedy even repeating the same line ("I should've known he'd smurf me.") after he falls for Jokey's present gag.
The first scene featuring Gargamel's hovel is a callback to the beginning of "The Smurfette", particularly Gargamel angrily demanding the Smurfs to "stop all that happiness" from his window.
In "All Hallows' Eve" it is revealed that Gargamel apparently believes in using corporal punishment on children when he mentioned he will give the children a "rap on the knuckles with his stick" for bothering him for treats. This will be later used in "Master Scruple" where Gargamel spanks Scruple offscreen.
"All Hallows' Eve" was originally titled "The Smurfs' Halloween Special," though it is a normal cartoon episode of standard running length and not an actual cartoon special. It was renamed "All Hallows' Eve" for the syndicated run.