Wordpress theme transition

[login to view URL] is in Wordpress [Online website that sells pet foods with 10 products, shopping cart, payment integration and about 20 pages] Current issue is the existing theme used. Although it is a paid premium theme, either there is bug in the theme coding or theme structure OR the developer poorly coded it. For example When we set new home pages with visual composer data its not working. We need to fixing the theme structure and theme templates files then we able to [login to view URL] are not sure if there is a child theme used, if at all, then what is the theme structure, what code have they used, if all custom fields can be removed or Can any modifications be made using Visual composer. 2. So we want to switch to a new theme but all need to look clean and professional. 3. This should resemble the look and feel of the existing website. 4. All the Menus, data, content, SEO tags, features, functionalities, Plugins, widgets, products and settings of the exisitng website to be copied without any loss. 5. New theme to have good theme structure, file structure & be able to Add/Edit content, product, pages, plugins without any problem in future. Remove all custom fields and design all pages in regular Visual Composer. 6. I don't want to face any problem that we are facing with the exisiting theme. Basically it becomes easier for us in future and convenient to add/update new content and new pages and manage. 7. No 3rd party website dependency allowed other than google. All css, js, font files must be hosted on our site. No urls of other non-affiliated entities other than google allowed anywhere is source code. 8. Include menu similar to that on current website, with menu buttons/links pointing to existing pages of desktop version of site. Basically copy all links AS-IS 9. Copy all content and seo tags over to new theme. 10. I want to be sure it is optimized for speed load and SEO and all the stuff like: 1. W3C validation errors 2. Broken Links 3. Image optimization [login to view URL] optimization [login to view URL] Image Alt-tags & broken Images 6. XML Sitemap 7. Canonical Error 8. Deprication errors 9. Title tags 10. H1 tags I want a third-party test report with screenshot 'after' for all the above issues SEPARATELY, so that I am sure there are NO issues and you have fixed them. 11. Ensure that there is no data loss or disruption to the exisiting live website. 12. You should take adequate backup of the exisitng website before switching. Preferably, before activiating the new theme, you should show a preview to us how it will affect the site. 13. You must make sure that your new theme is widget-ready. Sidebar widgets are really easy to use therefore we had customize it. Also anything that you modify in [login to view URL] file of your old theme, will be overwritten. So make sure that you add those codes in the new theme sidebar. 14. Ensure that you copy and paste your tracking code to new theme. i.e. Google Analytics 15. Once you have the new theme activated, you need to make sure that you retain all the functionality and plugins still work. 16. Test the site in all browsers and Mobile responsiveness you have access to and showcase the test results for confirmation. 17. Place on server can confirm functionality and Allow one iteration of the new design & layout if required from our side 18. Debug the webpage if any; Verify it for at least 3 days without any bugs Budget: 6500 INR Timeframe: 5 Working days