Magento SEO and analytics fixes and optimization for site upgrade

I will be launching a new Magento site for my client next month and need a bunch of cleanup on the old site so that we will not lose any page ranks on their site with google. They have about 2500 products in the database. I have mageworx enterprise SEO but it is not generating sitemaps and the one on the site is currently way out of date. there is 1000+ 404 not founds due to old sitemaps. I signed up for a MOZ analytics account and is showing 7773 duplicate page contents and some other various errors. I will get the newest mageworx SEO plugin and would like someone to get everything cleaned up, optimized and working well with minimal errors and duplicate content. We are trying to build the new site with matching URLs for products but will need you to go through and create permanent redirects for pages that are missing and perform other tasks to ensure we dont lose page rank. the site is [login to view URL] The winning freelancer must be a Magento and SEO expert and be able to deal with this issue quickly and efficiently.