Fan Translation: The SNES game was translated by fans and released far before the PlayStation version came out. The fan translation was far better than the official one, at least until the GBA version came out.
In the concept phase for the game, Exdeath had two designs, one of which ended up being discarded. If Square had not chosen for the villain to be a Tin Tyrant, he would have been a Demonic◊ Centaur◊. Parts of his alternate look ended up being incorporated to Neo Exdeath.
Also, early in development, Kelger was going to be human◊.
Minor boss Magissa's design was a prototype for Lenna. The final design has fair hair and longer robes.
It was originally planned for a US release under the name Final Fantasy III (which, of course, eventually became the number for VI abroad), and then a later attempt under the name Final Fantasy Extreme, due to the Job system being so much more in-depth than what the average RPG fan was used to.