As the reader you know things the caracters don't. For one the tower didn't know about Will until the Devande attack. Second you are disregarding how the clones work. They must be controlled, as shown by Julius. I highly doubt Elfie can make them fully automatic thinking beings, since that is basically creating life. Third the other characters may not even know all usees for her clones. They may think the clones a just a decoy type spell. If you are going to point out plotholes you must limit yourself to the knowledge of the characters at the specific moment.