That is my preferred breakfast. I prepare it the night before in a glass to allow the bottom layer tons of time to soften like you say but then I mix it all just before eating. I tend to use kefir since if I want fil I’ve gotta make it myself but as you say anything similar gets the job done.
I enjoy trying limited time flavors (of various brands and product types) and mystery flavors are no exception. My wife likes to as well so we’ll usually buy a single bottle to share and try. Despite liking the novelty it is pretty rare for me to leave the experience thinking, “I need to clear out the shelves before this goes away.”