Has anyone ever tried to make all three monster pallets into three separate monsters? I'm just curious of you could actually add little details like a variation in the face or armor? Because if that can be done than theoretically you could change job pallets too. To have physical variations instead of just swapping colors. Anyone ever tried?
That's not how palette swaps work.
You could bench a few colors on a sprite to obscure a detail that only really appears on another palette, but this wouldn't be terribly easy to do - the detail would have to blend in when it was beind hidden behind duplicate colors, and that'd mess with the shading for that area, plus it would limit the colors for that palette, which could very easily result in a noticeable drop in the sprite's quality.