OpenCart & Mysql Guru

Hi, We have recently installed an opencart 2.3.0.2 and manually copied certain tables from a separate opencart 2.0 installation (our old website hosted on a different server) to our new opencart 2.3 one. It have been experiencing the following problems which we need solved, preferably in this order: 1. The single MOST important task we need completed, is for someone to check our database tables structure integrity and inform us for any incompatibilities and/or dependencies that need to be issued. 2. When a customer places an order, their payment_zone column value and their shipping_zone column value in table oc_order receives a different zone value than what is listed in the available options in checkout. For example, they may have entered for their address to be in Attica, Greece and the recorded value would be Tasmania, Greece. 3. On our previous installation he had "Paladin SEO Manager" extension installed. After installing the same extension on this current installation, the extension messes up the URLs making the website non usable. We need for someone to properly install and configure this extension, as there are tons of external URLs previously leading to products in the old website that we need to link to products in the current website. 4. Whenever we manually add a product or whenever a customer buys a product from our website, our products stock is not properly updated. 5. We need the following extensions be installed and configured: - Newsletter Enhancements v3 vQmod free mega template pack - admin quick search - paladin SEO Manager - paladin sitemap generator - admin search customers and orders by telephone or postcode. * All aforementioned plugins we have purchased and had installed and functioning in the previous installation, Opencart 2.0 6. Three weeks ago we updated some of our products sizes on our old installation. Before deployment we manually copied our products table to update our stock. However, some products sizes were not updated. 7. When editing some installed extensions, at times we get an "Access Denied" error message which we can only bypass by uninstalling the extension and re-installing it. We need this problem solved too. 8. Whenever you go to our website for the first time, the default language is English. We need this to be set to Greek. 9. We had an extension named "admin quick search" in our previous installation that we need in our current one as well. We have tried to install it but not only does it show twice in control panel, but it also has most of the search fields not functioning. *** Please note that despite all the problems, the website is currently live, and all problems should be first be tested on a separate machine before aplied to the live website. ***