Minor WP theme tweaks, Code Fixes and W3C Validation

Hello all. We are looking for an experienced coder to perform some minor modifications to a Premium WordPress Theme as well as some fixes to the code. In detail, we're looking for the following: 1. WordPress Theme Modifications: a) We need an already existent Homepage block to display Most Popular Posts (based on # of comments) instead of displaying posts from a specific category as it does now. b) Add a widget at the top of the sidebar such as the one at [login to view URL] (Show your love to 9GAG) featuring Facebook Like button (for our Facebook Page), Google Plus 1 and Twitter follow button exactly as is on 9GAG. Obviously, this widget must "borrow" the same CSS style as the rest of the site's theme to fit in well. c) A piece of code erased from [login to view URL] (A Search Box that is built-in and we want it gone). c) Some text added in between the "Leave a Comment" text and the comment submission form (we'll provide example and text) d) The content area in posts and pages reduced to 600px wide. Just the text will do, no need to edit related posts thumbnails sizes etc. 2. Code Fixes a) We need you to test the site's code and fix all possible errors. We will provide you with every file you need to do so. This includes erasing pieces of code that create 404 pages and pieces of code that are unnecessary. b) Fix all errors and have the site pass W3C CSS, HTML and XHTML validation.