The plain stickman in this video also appears in the episode, PowerEdd.
The person with the DIR hat is a reference to one of Edd's older characters, DIR Bwain, who can be seen in one of Edd's DeviantArt pictures.
Along with The Matt Doll, this short marks one of the earliest appearances of Matt, Matt Hargreaves' cartoon counterpart and establishes his character trait of being overly sensitive about his looks, as he says that his ginger hair is "strawberry blonde".
The blonde stickman is called Joe, who used to be Edd's friend until Fall 2003.