Palettes question

Hello again, I have a question about the palettes :S I know how to edit it by FF3USme and change it ingame by windhex hehe, but I don't know how zeemis or angelo or gi attack or any other that are doing a real hack ffVI like the project of zeemis: The New FFIV... I don't know how they do to swapp many character's palettes without ruin the NPC... I mean, my problem is: I change Terra sprite and palette for Rydia sprite and palette (I replace the number 6 palette for the new rydia's palette) and in the battle palette I replace the 7, so in overworld rydia has palette 6 and in battle rydia has 7, and that was all cool I made my changes through windhex and all is fine, but in the save and shops, rydia shows grayed, I think because battle palette 7 in game is used to grayed a character... and that is no all, I want to replace cyan with cecil, mog with kain and setzer with yang (the sprite and palettes of course, and I see that all that sprites utilizes custom palettes)... How can I do it without ruin the NPCS palettes? How can I create custom palettes for that characters like you do in your projects? Doesn't matter if I need hex... hehe hope can help me. Thanks in advance.
PS: Like I told PocoLoco before I want rydia to replace her palette with the palette 9 of overworld but I don't found the code for that palette, in windhex I put code 12 and many others and the palette doesn't show up ingame... PocoLoko said me that only the palettes 0-7 are good the others are glitch... That's my problem ):

Poco or Nattak are the expert on palletes, but I remember while beta testing nattak's new hack that he had the similar problem with pallete #7. If you give a character pallete #7 he/she will look messed up in menus, the airship menu and the save menu because of a limitation on the game's code.

PM me and we can talk about this further, I'll help u out

Hey Angelo, I saw that you include golbez in your game, but how do you do that without mess up the npc palettes??

This type of question has been answered quite a few times before in so many threads -you may want to go and read those- before reading my answer.

All I know about palletes - which is close to nothing- in a nutshell:

Characters share a number of colors because SNES limits the number of colors for any character to be less than 12 (typically 16, but 4 of these 16 are used somewhere else).

The video you saw in which I used Golbez is because I replaced Mog with Golbez. Mog and Umaro share the same colors. If I edit mog, umaro will be affected as well. In the video, I didn't show umaro - which turned into a pink-ish yeti-.

Again, Poco or Zeemis are the experts in this topic.

i should keep this in mind for when i eventually work on my hack some more.