Custom code changes to my Square Space website

I need some changes to my existing website, [login to view URL] 1) For mobile, add a cart to the header, and show a "0" if it's empty (for desktop there already is a cart in the header, but show a "0" if it's empty) 2) On mobile, the gallery pages should have two images per row (make the images larger to appreciate) and add title and prices below the image 3) On mobile, remove the e-mail popup, and make it push up from the bottom instead. 4) For desktop, add my 1-855-952-7627 number at the top left with hours of operation "Mon-Fri 9am-6pm and Sat-Sun 11am-4pm ET" 5) On product pages, expand the "share" options for like, tweet, and pin it, and add e-mail as the main sharing option. All should be visible by default, without having to click on "share" 6) Cross-sell 3 unique other products on the bottom of all product pages 7) Add a social plugin on my homepage, above the footer, which allows customers to preview, scroll my feed, and "like" my page on facebook. (see [login to view URL] for an example--left side under "social") 8) Allow customer reviews for products and show them on my product pages just like amazon does. 1 to 5-star ratings, was this review helpful, ask a question, etc. Don't show review section for products that don't have any reviews yet, but instead show "Be the first to review this product". 9) Add a shipping calculator to my cart page that allows users to calculate their estimated delivery date (via UPS API) and cost (based on my website fixed shipping costs). Users can use this before they checkout. 10) Add a live chat option that I can toggle off and on manually, or set on a schedule. I would like to be able to respond to live chats via a text message if possible