Could it be:
* Zack, Slater, Kelly, Jessie, Lisa and Mr. Belding characters in this show?
* The entire Bayside High School in this show?
* The entire real-life original class series crewmember group?
Honestly we don't know everybody who has a 'disability' in the group. This is not explored.
Like most teen shows achievement and success are tied together and it is incorrectly implied that anybody who cannot achieve at the single standard level is not successful and will not graduate. This is not how a public high school in 1990's California would have been allowed to legally work.
As principal, Mr Belding could not prevent students with disabilities from enrolling and/or graduating. He--or an assistant principal would have to attend an IEP/504 meeting for every student who receives services. This is part of their duties as a school administrator. They have to ensure the special education department at bayside and/or the general education departments are providing appropriate services for every enrolled student who is approved for and needs special education services.
We do not see these meetings or the special ed department of bayside bc of confidentiality laws. But this has to exist because special education was previously passed in 1975 , is a federal law covering all public schools. So we have to assume that the students are recieving services and things are fine/it's not a 'conflict'.
We did see an episode where Zach becomes anxious after meeting Melissa whom he learns is in a wheelchair. Zach has to learn he has issues (aka he is ableist). And Zach still remains friends with Jessie after she has to get treatment for getting an addiction to caffeine pills---people in treatment for addiction are covered under the ADA. This is as far as it gets re high school accommodation. We don't instead see Melissa's family working with Bayside to negotiate adaptive PE requirements. Or desk accommodations. How would Melissa be evacuated from the building during a fire drill/fire? And while these issues are a bit deep for saved by the bell to tackle, they are all things which students with physical disabilities potentially navigate. Not surprisingly, Melissa is dumped after this episode and we never hear from her again.