Costuming desiree

To costume desiree, I think it would be fitting if she wore traditional and simplistic "lower-class" clothing, with dark, "earthy" tones of brown. This would be similar and in line to the dress of all of the others in her village, to show that she is, regardless of her own dreams of rising above, a peasant by status. However, notably she would have a few features separate from the other villagers. In my mind, I envision her to wear something such as a simple flower or clip in her hair, or tie it up in a braid, to imply and show  her eventual and temporary rise to high-status as well as her own fixiation that she is above the rest of the peasants, and meant to be so. Optionally, she could have a simple necklace, a cheap one so it wouldn't be some object of desire for others, but pretty enough to show that she isn't just a peasant girl in a small farming village.

The most difficult thing about costuming desiree would be to represent her connection to Agwe, which would only be necessary if Agwe were even to be portrayed. She would have something simplistic, again, perhaps a clip in her hair, that Agwe would also wear (or have some object similar to it) to show their connection.

In terms of costuming her post-transformation, when Daniel calls for fashionistas to assist her, I think she would wear something that would seem sort of like a mishmash of objects that don't really harmonize, but still manage to combine together to create a good mesh. I'm not really sure how this would work out, but that's just the base idea.