Likeness's
Here are a list of people I think look like Aya, Ceres, and Tooya. I will also add up thoughts of other people, just email me and let me know.
Aya Mikage
Kagome Higurashi - She reminds me of Kagome, because she is really peppy and has that sorta I'm going to go out and get it look. She also has a sort of forbidden love relationship with Tooya that Kagome has with Inuyasha. Her life is sort of messed up and dangerous like Kagome's. She has Ceres in her, while Kagome has the Shikon no Tama. Kagome has to fight against evil to retieve the Shikon Fragments.. Aya (as Ceres) fights to retrieve the feathered robe Ceres lost along time ago. So they are fairly similar in alot of aspects.
Ceres
Kagura - Ceres reminds me of Kagura mainly because both of them are being held against their will by a master/lover that is very power hungry. Kagura has Naraku her creator, while Ceres had Shiso.. a fisherman gone bad with the power Ceres eventually gave him. They both are very destructive in powers and have one thing they both hunger after. Ceres wishes to get back her feathered robe, while Kagura wish's for her freedom so much she'll do anything to get it. So they are both about the same for they will do ANYTHING to get to their goal.
Kaguya - Ceres is alot like Kaguya as she was trapped in the moon through a sort of semi-dementional looking glass. She was trapped there because along time ago she was also a Tennyo bathing and her feathered robe was stolen by a man, who she ended up falling in love with. It's almost exactly the same as the Ceres Legend, but there are alot of differences. She is stuck on the moon but can influence people from there to do her bidding. She must collect a variety of items and these items will help break the seal that binded her there for all that time. She comes out and retrieves her stolen robe from one of the other InuYasha characters. So the movie is ALOT like Ceres but with quite a bit of differences here and there. I'd advise seeing the movie.. it's wonderful.