Here is a naked fairy from Nintendo
serious answer now: If they don`t have a humanoid body, there is no nudity restriction.
Maybe if their bodies are covered in light and it doesn`t show genitals and nipples, it might not count as nudity? (better check just in case).....at least it worked on Sailor moon.....for scenes during a few seconds
Or you can make them wear "clothes" made of the energy-aspect they are....ex: a fairy of fire may just wear actual fire that cover her private parts but don`t burn her.
Also, a fairy with long hair may use her hair to cover her privates.....she would still be naked, but her hair gives the illusion of clothing and can be a fun design challenge.
Well, make sure to check the guidelines to see how they define nudity.