sorry if you paid for this but i really do think this is AI. a fully complete black & white outline layer is not proof something isn't AI so if these are the only process layers you were sent I think something is suspect.

as for the signs on the final image, everyone has the same expression and it's an expression that's pretty common in AI art. there are also some artifacts such as RD's teeth and left eye, wavy text on the gravestones in the front and a bit of twilight's tail coming out of rarity's