Website , Hi there, nice to see your project posted. I have understood the requirement of ecommerce store. I have understood the requirement of new theme customization, integration of payment gateway, adding existing products and customers, seo friendly, google adwords, chat etc. Can you please share the link of your existing website.
I have built customized ecommerce platforms with payment gateways. My ecommerce platforms were responsive, attractive, seo friendly, easy to edit etc. I have also worked on transferring content including customers and products in the past as well. I can share the references. I will be happy to receive response and move forward.