@LeviKornelsen
I wandered down this rabbit hope some years ago. Shapechanging overlapped with illusion, as both lead to disguises. The solution was to bar shapechanging from altering the face, with some Middle-Ages metaphysics.
"The face shows the soul. Red-heads transformed into a cat will become a red-haired cat"
So people show little clues about their identity, because some games need that balance.