I finally found the answer to my second question, which was a little confusing until one has some experience building a few libraries. As the moderator pointed out, under the "Playing Now" at the top of the Action Window, there is a list of libraries; the active one is highlighted by a green play button. If one clicks on the green play button, one is presented a list of options among which is "Rename". The option to Hide the Library, incidentally is not on that list, presumably because it is the active library. That option (called Delete) is present, however for inactive libraries.