Near the end of the main storyline, Evelyn and her father finally reunite.
Save "The Sadness Parade" until you can send Violet on it. Regardless of her opinions of the outcome of the dark ritual, the fact that it involved stealing from her younger sister raises her ire.
A significant number of Violet's dispatch mission quotes allude to her relationship with Poppy, in fact. Send her on "Episode X", for example, and she'll let slip that they used to watch Starcruiser X together.