Lucilla's Blue Germania Costume
Blue long sleeve v-neck dress worn with two darker blue wraps with gold trim under the fur-edged cloak. The underdress seems to be crushed silk. Some metallic scroll embroidery with small pearls around the v-neck.
There seems to be a gold belt or half-cuirass around her lower torso. This also seems to exist on her party frock. I'm still trying to get a decent picture of it.
I've been trying to track down what Lucilla wears over the dress on her Party Frock and her Blue Germania costume. I finally have some screencaps of what I think I'm seeing. It seems to be a gold or brown corset, though I don't have any concrete details. I think I'm seeing a corset with gold embroidery and a center front opening. I suspect that it's meant to be some sort of armor for her, as she wears it the whole time she's in Germania and then we never see it again. You can see it best in this images: