The specific colour is not significant. What counts is that Moby Dick was not the standard colour for a sperm whale and was therefor easily recognised as an individual. The story does not work if...
Moby Dick lives, at least in the novel, so I would also say he lives in the film. At the end of the book, Ahab has the chance to throw only one harpoon into Moby Dick, and it is the line from that...