Zencart Website Developer required.

Hi All, I have below requirements, kindly go through and let me know your bid. Zen Cart Ecommerce upgrade 1. Update Zen Cart to latest version from v1.5.5f to v1.5.7 (very easy) 2. I have a paid for and currently installed zen cart template (Your Store) which as an available update. I would like you to update this also to make more compatible with the zen cart update . Some custom code exists for google translate and to turn off the top category bar on the front end for mobile and desktop (a fresh install of this can be done if you think easier but it is not difficult) 3. Add square payments which is a plug n play from zen cart. Just needs configuring developer end and my end. 4. I want to stream line my checkout with a One page checkout for zen cart. I need this to be tested as working on mobile / desktop. [login to view URL] should not lag after work complete and work should be carried out with optimisation and site speed in mind. Any duplicate files etc that slow the website can be removed if not necessary. You will know what to do. 6. Maybe reduce image size and other things that slow the website you can see google site speed test which can show what needs improving) 7. SEO support and suggestions that you think could improve the business is appreciated. I would love a fast and easy to buy from website with checkout process. Future and semi regular work will be available for the right person on projects. 8. I may want to add other simple things like adding Trust pilot BCC to email customer and 'buy safe' widget or similar to show website is safe and secure. The website needs to remain responsive. This is ultimately upgrading 3 upgrades and a plug and play payment facility. The only slight challenge is the one page checkout and responsiveness. Website already operates a very responsive theme. Thanks and Regards.