Changes to a WordPress blog

1. Merge two blogs which are already running from the same WordPress installation, but are currently displaying slightly varying information in the templates (different header graphic, different description text and authors in the side bar, different subcategories, etc) and also have unique category slugs in the URL; this is currently being handled via selecting one or both of the two main categories for each post (so each post could also appear in both blogs simultaneously) 2. The goal is to have no more distinction between the two current blogs, so there will only be one header graphic (graphic existing), one description text, all subcategories will be merged, as well as authors, post archive, RSS feed, related links, and the unique category slug in the URL needs to be removed