I am getting close to texturing things and wanted to be sure that I am able to use emissive and metallic materials. With the included colors of course.

So can I?

Cel shading.

Personally I wouldn't mind as long as they are not too bloomy or reflective, but I don't know how harsh the other contestants judge.

If the reflections use just the colors of the palette it is allowed. If you have lights in your scene you have to use cel shading so only the allowed colors are used.