Bloodnight
Author-sama, I would like to help with that! A while ago there was a crossover of DxD with a Senran Kagura gacha game, and the character Murakumo cosplayed as Gasper as part of the crossover, creating the arguably best example of a Female Gasper I have ever seen (Only different thing is that the eyes should be red because of Gasper being half-vampire, but still XD):
Bloodnight:Ok, then, you'll have your fem Gasper, this author don't care about anything, i don't mind if the girl is a loli or no, so you have luck :)