imho, the textures should be as simple as they are allowed to be. for example a leave could have one basecolor, some veins and maybe some dried out browns. thats it. skin should have one base color and if you need a tattoo or blood another color for that. wood should have some basic structure consisting of two or three colors...

for the lighting i guess best would be if it reacts to all lights possible, just because you may wish to have torches, explosions, other light effects aside the sun/moon light

btw, there are ways to create toonscenery as a postprocess