is there any way I can edit Luigi's sprites from Super Mario World? (yes, I already tried to extract all the Graphics/Sprites but it only has Mario's sprites)
The Luigi graphics are not kept like the rest of the graphics in the game, they are already uncompressed in the rom. I don't believe Lunar Magic bothers to extract those, which is likely why you haven't been able to find them. If you open the rom in YY-CHR, put it in 4BPP SNES mode and go to address 12000, you should see them and be able to change them there.