Do you happen to know how much free space is in an average GBA rom, or more specifically, firered? I'm a little little bit concerned about space usable for the hacking of my rom, but it's just a curiosity really.
And, again! I managed to change the palette and greyscale sprite for Red in the intro successfully but when I booted up the rom in VBA, the colors were all messed up. Re-extracted the rom from it's zip folder to get a fresh rom, and opened up NSE again..only to find out it's not letting me replace the greyscale sprites in the intro. I suspect it may have to do with how I'm making my custom intro sprites into greyscale versions, but I'm not sure.
Changing Oak's sprite in the intro. I'm trying to follow what you told me, i.e with the "click 256 colors and replace it be sure to have it in the same canvas size of prof.oak and then go edit the pallete in APE although the sprites' pallete in the intro or somewhat connected so it will be really hard to replace those"