From his grammar it appears that sweat209’s first language is not English, which may be contributing to all the confusion.
It can be shown with many other examples that how you pronounce a letter may have little or nothing to do with how you pronounce a word containing that letter. I am pretty sure “G” is pronounced in all English accents as “Gee” with a soft G. “Goat” is pronounced with a hard G and a long O following it. “Gem” has a soft G, “Gear” has a hard G. And so on for many other letters.
For a really extreme example of the difference between pronouncing a letter and pronouncing words containing that letter, consider W.
So the fact that I say Zed and the folks south of the border say Zee has no relevance to the fact that we both (I think) say Zero with a long e. I had an east indian TA once that pronounced Zero as Gero with a soft g, which was damn confusing until I realized what he was trying to say!
So, you can discuss who in the world says Zed for the last letter of the alphabet and who says Zee, but words have nothing to do with it.