Magento Naviation Re-Work With Categories

We require a talented Magento freelancer to help update a navigation menu. The items which will be updating are the navigation names, the category names will need only minor alterations, and the navigation requires dropdowns adding. The client should also be able to easily rename and add dropdown menu items if they wish to do so. We also require 301 redirects for any categories or URL's we change for the category and products. We have the design and all the category names formatted for easy reference. We have a development website set up and ready to start, we do have one question which we would like your guidance on, which is what is the best way we can implement the menu and transfer this to the live website? As the website is constantly taking orders, we don't want to overwrite these as obviously the database will require changes for the categories etc. So we'd like suggestions on how to do this. We believe that's as much information we can offer at this stage, but are happy to answer any questions. One thing to note, for freelancers who decide the increase their bid, they will instantly be rejected so please bid fairly. We require the work to be carried out professionally and to a high standard so bare this in mind as we won't accept poorly coded or designed work. Another note, do NOT contact the client direct as others have done in the past - this will result in an instant rejection also.