you can change the colors and stuff by talking to her with a special action/command you get from getting her
I don't remember how exactly to have it on the hotbar, but it's the same way you change between consumables, was it holding it? I forgor
about the what scenes I have no idea, there's a dialog in the last "city" in a bar, go where the girl with the backpack is and go downstairs, but that's all, just a dialog, it's all I've found (plus an "I'll be back" dialog when you excorcise yourself via crystals in the hotsprings)