Possible origins of ideas in Spirited Away

I think I have discovered a ghost... In a true story, written about a very real prisoner of war, who became slave labor during thre war years in Japan, and who was celebrated in the book and a recent fil, Unbroken, at the very end of the war, the Australian and American prisoners of war were allowed to bathe in the Kohaku River.  Perhaps there was a plan to kill them all, but they were saved when an American plane flew over and spotted them, so their existance was known and they were not killed - something they considered a miracle; and these prisoners of war had been used to load coal - becoming human  "soot sprites":. Following their release, they invaded local bath houses by the hundreds, trying to get the coal dust off.  Could these carefully forgotten shadows be quietly haunting this film?