Build ecommerce grocery store based on theme template and set up using Wordpress and Woo Commerce

I am looking for a ecommerce developer who can create skeleton site (no graphic design required) containing a bulk food grocery store. I am keen to use the following theme: [login to view URL] but it will need modification per below. Two things I am keen to ensure: 1) Site is FAST to load 2) Customer Experience is GOOD. I'd need recommendations on above to get best outcome please. Site will need to consist of: 1) Homepage: which doubles also as the main shopping page (I do not want to default to having people click into specific products to add them to the shopping cart). I'd like every product in a small format available to order from this page, with a nav that helps you jump to different parts of the page (because this page could be really long potentially). This Nav needs to be easily accessed when shopping on mobile device too. Within the 'add to cart' elements of this home page shopping experience, I also want customers to be able to select sizing of product (i.e. 100g, 250g, 500g, 1000g, 2000g). This page doubles as a quick way to start shopping. 2) Product pages: All products require detail pages with images, select size, add to cart etc. 3) About us 4) Cart 5) Help Centre Also needs 'My Account' where you can login to see historical orders, prices, shipping addresses etc. This will need set up too. Once set up, I need to be able to maintain through back end, adding products easy, modifying prices, adding specials Also needs connectivity to payment systems - looking for recommendations between Paypal, Stripe and Square. This will also need to be set up.