Re the N word, an interesting case in point is the opening chorus of the musical "Showboat", by Jerome Kern and Oscar Hammerstein.

The original chorus went something like:-

"N****** all work on the Mississipi."

This went through various stages such as:-

"Darkies all work on the Mississipi."

"Colured Folks Work on the Mississipi"

to "We all work on the Mississipi"

until finally, no one worked on the Mississipi and the opening chorus was omitted completely. The accompanying article is quite enlightening on OH's original intentions:-


New Statesman article