Silvergale's Aria missing pieces?

I've completed the Silvergale's Aria Miracle Outfit and somehow I'm missing 4/12 on this achievement. Does anyone know what am I missing? What are we supposed to get?

I've completed the Silvergale's Aria Miracle Outfit and somehow I'm missing 4/12 on this achievement. Does anyone know what am I missing? What are we supposed to get?