mariel, normally plain whipped cream will not freeze perfectly, and this cake has a whipped cream topping. I don’t know if the powdered coconut will stabilize it enough to allow it to freeze, you might consider asking Rose directly over on the blog. You can find her Cake Questions three thread through the topics in the sidebar, or just do a search.
I would recommend stabilizing the whipped cream with gelatin to be safe, and then freezing the cake as soon as it is cooled and assembled. Butter cakes don’t always remain moist over several days in the refrigerator.