Don't you worry guy, I got you! I actually wanted to do the exact same thing as you, switch out all the Main character graphics with my own, except I was aiming to change the Female MC ones lol. So anyway, there is a horrible lack of tutorials on the web/youtube about editing character graphics (except sprites, seems everyone knows how to do sprites). So I started digging around the rom using Tinke, and eventually I found a reasonably easy way to get my own sprites in to replace the originals