Reasonable explanations for characters mysteriously leaving

I remember watching every episode of this show when I was a kid and I was peeved that every season it was more and more cast changes. After the first season, i mainly watched just to see who was staying and who was gone. After watching a few of these episodes again, I came up with reasonable explanations to why certain characters left.

Scott- realizing that he wasn't going to win Lindsay, all of his schemes backfired and landed him in detention, striking out with most of the girls in the school, and with Vicky essentially stalking him at every turn, he thought it was best to return to Valley.

Vicky- The California climate was too much for her various acne and sinus problems so her and her paents moved to a different state where there would be less factors to irritate Vicky.

Weasel - Realizing that he had a hidden gift as a field goal kicker and seeing how easily he was persuaded, a girl from a rival school (possibly Valley) probably suckered him into transferring to kick for their football team.

Megan - Presumably got a scholarship to some ritzy California prep school (possibly the one from season 1). Since most of her closest friends from season 1 left (including her best friend Vicky), she probably the prep school on their offer thanks to encouragement from Belding and her father. Seeing as serious as she took her schooling, she probably realized that public school wasn't enough of a challenge for her.

Brian - foreign exchange students only stay for 1 year, so he probably went back to Switzerland at the end of the school year.

Ryan - Probably transferred to a school in New York to be near Rachel

Rachel - As fashion conscious as she she was, she probably transferred to a high school for the arts in hopes of one day becoming a fashion designer

R.J - Found out that he fit in better at Valley and decided to transfer back there.

what you guys think?