Monster Palettes

Easy question (I think) that I could not find the answer to by searching this forum. Are Monster/Esper palettes shared with any other graphics in-game (besides other Monsters/Espers)? If I go and change a random monster palette and all the monsters/espers look ok, am I still in danger of seeing some screwed up stuff in-game, like the overworld, weapons, characters, etc.?

I ask this question, because I have already used up all the blank palettes (the black ones) from 657 to 767 in FF3se. I think some of the other palettes are now unused since I deleted/replaced quite a few default monsters.