Many thanks for a stimulating and informativa article. Having loved the film for many years, I recently got round to reading Kazantzakis' novel which I found very rewarding, particularly for the extra information on Zorba's biography (both before and after the events portrayed in the movie). .While I really enjoyed the book, and have been inspired to read other works by Kazantzakis, .I feel this is one of the few instances where a movie actually adds something extra to the original work. As well as all the wonderful elements you mention, for me the vibrant and compelling soundtrack is an essential part of the film's magic.
Just to prove that I'm a complete Zorba anorak, I recently took my family on vacation to Crete. If you ever go, I recommend a visit to Kokkino Chorio, a tiny hilltop village which is still recognizable as the backdrop to many of the scenes, as well as the dramatic Stavros Beach where they shot that overwhelmingly joyful finale! Excuse me while I go and watch it again ...