The key to being a "Moon Elf" or a "Sun elf" or many of them, is embracing the element of that wing and using that to base them on.
For instance, a Moon Elf who has lived there her whole life, has the moons in her eyes and black scelera. However, most who saw her would know from a distance based on the symbols she chooses, outfits, ornaments. The elements are how they evolve are so much of an elfs' life, that it is essential to their core and thus they tend to "represent" their element.
Some of the Elements that evolve with an elf, might go from water, to weather, to storm. As the elf changes, the element does and as they both grow together, so too, does their preferences.
Basically, I don't want too many barriers for someone to create an elf, or wanting a moon elf, but loving star aesthetics. I want others to have fun building and creating, but also, the less complicated it is for me, the better it is for me to remember all the do's and don'ts haha!
Note: Starfallen Elves are the only ones who can transition to another, but not vice versa. There ARE Elves with Starfallen blood, but they're born in the Westwing under the moon. They're born with stars in their hair and moons in their eyes and they are accepted by both, however, the elf wants to follow the stars and moves along that path to find them.
Even Demikins can be affected, but its a bit more difficult due to their lineage being between an elf and a nature spirit (nymph)