Music from the Soul

Based off the Tumblr prompts: (1) Imagine going for a walk and listening to Castiel tell you about the stars singing, (2) Imagine showing the Winchesters and Cas your musical ability, (3) Imagine Cas singing to you when you can't sleep, and (4) Imagine teaching Cas about different types of music. Castiel, female OC, ONESHOT, slight AU for Season 9, mentions of canon character death