In line with William's comment about the refrain from putting Mickey into the game until the results were known there is an interesting change near the end involving his, the King's, Mickey's, revealing at the door to Kingdom Hearts.
When King Mickey shows himself Goofy and Donald exclaim "王様” in the Japanese version and "Your Majesty" in the English version. King Mickey tells them to close the doors, but Sora worries about what will happen. Goofy calms his fears, but there is a slight difference. In the Japanese version Goofy says, "ソラ、王様を信じよう！" In the English version he says "Sora, you can trust King Mickey."
Whereas the Japanese version is unable to use the word Mickey in the entirety of the game, thereby limiting Mickey's existence beyond as an icon, the English version (and the subsequent International Version) insert the one verbal notation.
What does this mean toward logistics of using Mickey? Had the game simply garnered enough attention or been seen as positive enough by the corporate/bureaucratic powers that be so that the English dialogue was able to legitimately insert the name Mickey, or was it a matter of imbalance?