Kefka refuses to change palettes even when Hex Editing...

[madsiur]

Man, I must start my hack over, since the program crashes when I load my hacked ROM...

You can do the changes without the editor. All you need is the NPC document which will give you the offset of your NPC, given you know exactly in which map he is but there is a relatively good map description in the document. You can found the NPC document on izmogelmo's site.