We could do a sprig of sage instead -- since it would match your colors Lovely idea- sending a wedding invitation tied with string and sprigs of lavender. A nice surprise and sets the atmosphere of naturalistic whimsy.
I am not sure about soap idea? Lol but I like how the they wrapped these favors then out in vintage suitcase! Wedding Favors - Lavender Soap wrapped in kraft paper and twine, topped with a colorful sprig of lavender and displayed in a vintage suitcase.