What was the original Mac's (1984) development stack?
Actually the original Macintosh development environment was not on a Mac at all. Quoting from this article on Folklore.org...


  Macintosh development in the early days (circa 1983-1985) was done
  using the Apple Lisa computer and its Lisa Workshop development
  environment


Most of the stories on folklore.org are written by the Apple employees who did the work and no longer work at Apple. A fascinating site. Careful, once you get started you may not come up for air for hours.