Continuity mistake: In the episode, 'Backpack', when Zoey and her friends are confronting Stacy, the shot goes to behind Stacy and Nicole says, "You're not closed." At this point, the side of the sign on the table facing Stacy is blank. Then, after Michael tells Stacy that she can't close a table, Stacy flips the triangular sign so that the side that was just facing her (the blank side) is now facing out to Zoey and her friends and has the word 'closed' on it.
Other mistake: When Stacy sees Zoey's designed backpacks for the first time, she uses her camera to take pictures of them. In one shot, a close up of the camera display is shown and the message "CF card full" is on the display and yet the camera still makes "click" sounds as Stacy seems to take pictures. (00:10:22)
Answer: Dustin was only considered a main character from season 1-3, and probably just because he's Zoey's brother. Dana was only a main character for season 1 and James didn't become a main character until season 4.
Bishop73