リリィ is a common way to write it, although I’m not sure why it’s more common than リリー (perhaps just cause the ィ is more of a phonetic addition rather than a semantic one). Here’s a list of fictional characters whose name is spelled リリィ. It’s probably supposed to be a less obvious way to evoke the idea of yuri. There seem to be a couple other series that have had similar titles like “Comicリリィ” or “アサルトリリィ Bouquet”.
Anyway, the “Lily” isn’t the only remarkable part of the title, what does “Momentary” mean here? Leave it to Japanese pop media to take random English words to make titles that kinda work? but wouldn’t really work well in English. Shoutouts to “Battle Tendency” and “Delicious in Dungeon”.
But yeah, it’s definitely not a localization of yuri/ユリ/百合 because the title doesn’t say that at all.