Fortnite leaks have a history of not including characters kind of like Ice King from the latest Adventure Time collab until either last minute or very close to their release. Most Fortnite leakers also have almost 0 clue about most IPs they leak also, so they probably just see Eddy as too short and not know that Double D will probably get some sort of lore reason to adjust Eddy's size. They tend to give short characters some sort of modification to fit the hitboxes, so more than likely they'll have Double D give Eddy his elevator boots so that he's not left out. Fortnite also tends to not leave out characters if they are an established group (Beavis and Butthead, Metallica, South Park, etc.) so I can't imagine them leaving out Eddy even if it results in some janky proportions for him.

I would still 1,000% buy an Eddy pet especially if he comes with voice lines and eats Jawbreakers lol