7 Complex Shopify tasks

Hi, I operate a Shopify-hosted designer dress hire website called Never Twice and use Book That for booking management. I am upgrading to the Symmetry theme provided by CleanThemes and need the following done: 1)Product page - 'total' label to show after quantity and before add to cart button, with value calculated based on number of days for the hire (working currently in my Brooklyn theme, so can't be that hard!); 2) Home and collection pages - filter by date available based on Book That and what's in the particular collection (this might be a little more complex); 3) Home page - Make size tags and sort by options work (currently not sorting) and make size filters show at all times but be able to be hidden (hidden is current default); 4) Product page - 'per day' label next to variant price (the 'per day' label is showing in the collection page. The label is also showing on the product age in my current Brooklyn theme, so can't be that hard!); 5) Cart page - quantity read only; 6) Cart button - pluralise 'dress' when two or more dresses are in the cart (do not pluralise based on days/quantity of each variant in the cart. This will probably make more sense when you see the site; and 7) Have my Book That booking dates pull through to my customised email order receipt app. FYI, the 'home' and the 'all collection' pages are identical. The theme for this work to be done on is not currently live, but I can give you access and you can preview it :) All coding need to render beautifully and not adversely impact on page load times please. Please reply with your experience with Shopify. Candidates with experience working with Book That will be favoured. Let's do this!