I bought the forest wisp after reading about the drops. Like reported by others, I had been receiving 3 wisp essences and a newborn sprite with each collection. This morning I received essence (not sure how many), but no newborn sprite. This was probably my 4th collection. Still worth the purchase, but thought I’d report that we may not get a newborn sprite each time.
Thanks to those who suggested collecting additional items before finishing part 1.