While you can use a Spanish language pack in order to change the localisation of the software, the rest you will have issues with. It will detect language based on the browser language, you cannot base permissions on that, so would not be able to do different forums for different languages and have them automatically hide based on user. Same goes for the theme. In addition to this, the URL side of things is something you would need 2 licenses for in any case, as your licenses are per URL.