Because I'm not sure if I've written the relationships of the family shown early in the chapter in a coherent way, or maybe haven't presented them in a way that readers will be able to get, I'm going to explain it here, behind spoiler tags in case you want to try to figure it out yourself and then check your work against what I had.
Read Chapter 13 first, although that should go without saying.
Okay, so, Goofy is Goofy. This is the Goofy that is close friends with Mickey and Donald, and the most visible Goofy in most material. This is also the Goofy that is shown in Cartoon shorts married, with a kid named, variously, Junior, Buster, or George. He is also the first Super Goof. In this story, he is the one shown briefly reading the newspaper.
Junior is another Goofy. This is the first Goofy's little boy from the shorts where he was married. I went with calling him "George Goof Jr." and relegated "Buster" to just one of those things parents say. I also decided that since "George" is the closest thing to an official name we have for the kid in the shorts, and he is also known as Junior, we can assume that the original Goofy's name is actually George, and Goofy is a nickname. I tried to call him "Junior" mostly to keep that from getting confusing or too controversial. When he was grown, this Goofy went off to Saint Canard with the super-goobers to inherit the title of "Super Goof." Later on, he married, and had a child. Then I guess the Fridge lanterns got to her, because there is hide nor hair of her in Goof Troop. Not long after, the events of this story occurred and he was forced to move in with his father, Goofy, in Spoonerville. This is the Goofy that we know from Goof Troop. If you don't know, this is Junior, who Gizmoduck tried to interrogate.
Max, is, of course, the baby. Goof Troop happens chronologically after this story, in about nine or ten years, after the original Goofy, Max's Grandfather, passes away.
Hope that made sense.