Here's what I found that you could change:
Barret should revert to his old brown palette.
I would use my patch that edits the opening area I gave you.
The Soldiers colors in-battle have weird colors. The helmet glass should be yellow.
Cloud's mugshot is all yellow, the top part should be yellow and the bottom should be blue like the status screen.
Aeris' status screen background is gray and not black for some reason
That's all I found. Good job so far
Tell me what ideas you accept or decline.