At least in my opinion, none of that excludes non-pixel art. The first section there doesn't limit the definition to pixel art specifically. Vector art can be simple too, it's just a little different. Real textures have curves lol
The rule about mixing palettes and adding colors simply means that you cannot alter the palette that you choose to use. Meaning, you have to make the best of the colors you've got. It does NOT exclude anti-aliasing or anything like that. Those sorts of techniques have no effect on the "simple-ness" of the textures, so it shouldn't matter much.
Anyway, that's just my opinion.
I would have to say though that AA goes under the "Does not rely on filters" part.
Your pack would be completely acceptable if not for the AA.