Artist Commentary:

プリズムリバー→楽器屋
妖夢→園芸場
幽々子→　呉服屋

Prismrivers -> Musical Instrument Shop
Youmu -> Horticulture place (Literal)
Yuyuko -> Drapery Shop

I kinda see yuyuko as more of an assassin due to her ability to invoke death.

I was thinking black dye because of death, but the Japanese associate white clothing with funerals, not to mention I can't really read the hiragana all that well.

It says "sumizome", but i don't know if it means "Black Dye". All i know is that Yuyuko's theme is "Bloom Nobly, Cherry Blossoms of >>>Sumizome<<< ~ Border of Life"

Yuyuko, Queen of Drapes!