For Aria probably something with black around her body as a base and something grey/transparent for anything flowing. Maybe some decorational-only armor on her wings, golden some golden details or small jade lines on the dress and jewelry in mane and tail. Jewelry probably with thin golden frames and the jade stones inside. Something long on the dress to work with the long legs. I'd probably also put some sort of collar that goes up at the back of the dress. For Lucy, I'd also suggest black as a main color and maybe some vaguely transparent black stuff as well. Lace and embroideries. Some silver lining as details in the dress and some small patterns with the rose colors of her gemstones. Lace color going up her neck maybe as well as something lacey almost like sleeves reaching to the forelegs.