Check for bug on OnePageCheckOut + Restore landing page from backup + Install extensions.

We are about to go live with new design and new Magento backend. We need help to complete the pending tasks (in prioritised order) below before we can go live: * check the onepagecheckout (seems to be a bug/conflict bw OPC and shipping extensions) for completeness of orders. * restore landingpages for the top menu from backup (does no longer show after data migration, backup before the migration is available) * Link productpages to brand categories * redesign size filter/size displayed on product and category pages * Install extensions from our live server (copy the code?): Bubbleshop; Easy PopUp, Queryfier, Fullpagecache, Stockmovement - Zopim chat - Enhanced Admin Grids (+ Editor) - Datafeedwatch - Sofort banking/payment - Klarna payment/account * check the speed of the sites and optimise where possible (e.g. move Trustpilot feed to head tag and similar issues to optimise the speed) * optimise the design on mobile (responsive) Project is marked as minor due to most of the tasks are related to already available material (extensions and backup). NOTE: Only bid on this project if you have read above in details and have the time the next 24 hours to complete the tasks. * More tasks to follow for the right freelancer *