Website tune-up (Joomla based)

We need the following topics to be addressed for our website: - RSS link / error - Add Dublin Core support - Fix W3C Validity - Extension to track & fix (redirect) page not found errors (404), if possible non commercial - Search-box make-up - Suppress "Be the first to comment messages" - Slow page speed: supress inline styles, merge CSS files and JS files using some SEO / compression extension (We are using a [login to view URL] template), ideally non-commercial extension here too