1. Derived from Leilani*. The extra E at the end says She is truly one of a kind; unique.
(*Leilani is a Hawaiian name that means Heavenly Flower)
I like the meaning of Leilani, but we'll spell it Leilanie, because we know she will be one of a kind.
If you were in a room full of heavenly flowers and had to pick just one, Leilanie would be that one.