Mandela Effect is just the most de-bunkable conspiracy theory that ever existed. I know. Look at the "effect" that has suddenly made Canberra the capital of Australia! Or introduced those weird flying fox fruit bats to the world! Except - I live in Canberra and we see flying foxes a lot. So, debunk 1 popular myth. I could keep going on the geological changes that have supposedly occurred, but let's move on.
Looney TUNES - Tunes is only pronounced Toons in the US. In English speaking countries it is pronounced TYUNES. I was definitely Looney Tyunes. Toon Town came out of Roger Rabbit in the mid 80s.
Find physical evidence of the spelling changes, should not be a problem. Most are US products and do not affect the rest of the world, so a US thing? Or just bad education?
And as for the namesake, why if Mandela died in 1983 was a song released in 1984, that charted all over the world "Free, Neldon Mandela"?