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.
This is really cool! I really like how you designed everything, it looks amazing ^^ I can't think of anything for my OC, she's a tough one, she's not girly at all, and she isn't much for dresses... but I still can't think of anything ;-; I've been working for it for... meh idk xD 2 weeks or something, and I always fail.
Thanks! Ah I can understand that problem, not going for dresses is hard. If you can't do a dress, you can either go full-blown tomboy and make it a suit or you can attempt to make it look like less of a dress. Like, add more parts on the front of the pony like a choker, the part where the saddle would be, etc. Then instead of a dress for the behind, you could make something more like a sash.