Spike Lee was the first person offered to direct the film after Russell Simmons saw School Daze. Lee politely turned it down and wrote and directed Do the Right Thing instead.
Although he was never seen on screen, Eddie Murphy spent a lot of time on the set of the film hanging out with Run DMC and crew.
Vic Noto(Bartender Steve)who gets his fingers broken in the Alley,improvised most of his Dialogue at the bar With Jam Master Jay who although taken by surprise,played along well with the "Changes". The next day in Times Square after the Nightly Screening,Vic Noto was coincidentally approached By Spike Lee who praised his work in the film.
The film was shot in late 1986 for a small budget of under $300,000 then the producers raised some more money(a few hundred thousand more) to put into post production thus the delay in the release. The Spike Lee timing should be more like Russell offered him the film in early 1986 prior to production later in the year meaning he probably saw She's Gotta Have it and Spike turned it down and did School Daze.