Concerning the audio pitch, all you have to do is listen to the songs (there are plenty in the movie) on the audio track, and then to their vinyl or CD counterparts. You’ll hear the difference instantly. They sound miserable on the movie soundtrack.
You can also switch to the french track (available on both the 2009 and 2016 Blu-rays) during the musical cues. This track is pitched correctly as it was not altered in any way.
Never really knew if this pitch correction was intended or if it was a mishandling when the remastering was done in 2002.
Is it possible that Universal/John Landis were trying to avoid music licensing issues by changing the pitch of the audio? The reason I bring this up is because, sometimes when someone posts a clip from a movie/TV show on YouTube and the uploader alters the audio to avoid copyright problems. And also Universal has dealt with music licensing issues before on home video releases of films like Fast Times at Ridgemont High, Sixteen Candles, Weird Science, Nighthawks etc. So, could that be the case as to why the pitch of the audio was changed?