That is really pretty. For the stiffened fondant, you can use 50/50 paste, which is half gumpaste half fondant (or half flowerpaste half sugarpaste if you are in the UK, or aust, etc). But I would just use some tylose in my fondant (or CMC) those are products which also produce a modeling paste. You'll have to prop the fondant up until it dries though Then it does indeed look like the decorator went over the edges with royal and brushed it. . Love the look.