Emilie's demo, Iridescent Trail, (虹彩行迹) uses similar wording to the Iridescence Tour (虹色巡回), and can also be translated as Rainbow Trail. This is why the rain lets up when she releases her casket in the first scene, and why later on, she talks about adding scents to water: her perfumes bring the rainbow after the rain. It's fitting that Emilie is the one wrapping up Fontaine with her symbolism of bringing a rainbow after the rain.
This connection was lost on me initially, maybe because "iridescent" doesn't connect as strongly to the meteorological phenomenon as "rainbow" does. I do like that the terminology is consistent with the Iridescent Tour, even if they're unrelated.
Links
Character Demo: "Emilie: Iridescent Trail"
Misc
