Roxanne and Max are still together, but at separate universities.With all of the trouble the writers put Max through in the first movie so Roxanne would even consider dating him, they probably didn't want to cheaply undo that just for the sequel. That's why they had P.J. hook up with the beatnik and Goofy hook up with the librarian instead.
Roxanne dumped Max (or vice versa)That explains Mona and her lack of appearing beyond House of Mouse. Not soon after that appearance, they broke up. It's not like high school sweethearts always stay together anyway; very few do, you move on to new people.
Pete and Peg got divorcedPeg got fed up with Pete's money-grubbing schemes and demanded a divorce, taking Pistol with her and leaving PJ with Pete. Most likely why Pete's Jerk Ass meter went up in this movie.
Stacey's popularityI've come up with a number of explanations for why Stacey is popular despite her geeky appearance:
Mickey's Twice Upon a Christmas takes place in a different continuity from these moviesThose movies don't look Goof Troop canon so why would Roxanne exist and/or be with Max?
PJ never went home to visit. Not even once.This is related to my WMG on the Classic Disney Shorts page explaining why he didn't become a Canon Immigrant with Max, but... just within the Goof Troop universe itself, it seems abundantly clear that PJ is much happier immediately after leaving his house. Max says "see you at Christmas" to Goofy; no such line is delivered to Pete. Pete is Demoted to Extra more and more, only appearing in two scenes—three if you count one flashback to an earlier scene. The only interaction they have in the entire movie is in the first scene, and it's more-or-less indirect. And the movie ends with PJ, happily talking openly to his new beautiful girlfriend in the background of Max and Goofy having a father/son bond. It seems obvious that PJ's happy ending can only exist in a world without Pete. (This is assuming as fact that Peg and Pistol were split by divorce, and that he went to visit them occasionally.)
PJ followed Max to college on purpose.Considering how long their relationship has lasted, the fact that Max was for a long time the only friend PJ ever had, and his homelife, PJ probably considers Max the closest thing to a supportive family he has. Additionally, when Max threatened to transfer, PJ, who had already gone through his Character Development, became very frantic, panicky, and upset—a relapse. Max was part of PJ's safety and security once he left home.
Goofy didn't finish college because of MaxGoofy does not seem like a lazy student as he studied hard and got good grades in the movie, so why did he only complete 3 years of school? Because his girlfriend/wife got pregnant and he had to drop out in order to get a job to support them.
Kimmy (Goofy's photo baby) is Roxanne's sister.They have similar head shapes and noses (in a universe where that means a lot). Further, we only ever see Roxanne's father, and likewise, only Kimmy's mother.
Max at some point in his adulthood changes his name to George GeefIt could be that his embarrassment of his father got worse, it could be that Max got in trouble with the mob (and ended up with his ears chopped off). Either way, the fact that Max looks like the George Geef version of Goofy suggests that there may be more than a mere shout out or gag.
Max and Roxanne broke up because Roxanne's dad is a Child-Basher Basher.He thinks the innocence of childhood should be protected at all costs. While strange boys who come to see his daughter get growls and glares, people who treat their own children badly get to meet his fists. Well, after Max's best friend's dad and girlfriend's dad met, the former gave Max a Sadistic Choice—either break up with the girl or never see his best friend again. Max reasoned 1) his best friend needs him more, and 2) they'd known each other longer, and made his decision.
After An Extremely Goofy Movie ends, Team 99 pursue completely different majors.One thing that makes this group so interesting is their different intelligence talents, but unfortunately this is ultimately leading them down different paths. Max is a business major, putting to use his charisma and ambition for something more. Bobby is a computer science major, putting to use his tech-savviness. PJ is an English major, putting to use his talent with words. And then they have incompatible schedules in different parts of campus for three years, barely getting to see each other.