Two websites similar in nature need minor edits

I have two websites hosted on the same server that need the exact same edits.... the sites are as follows: [login to view URL] and [login to view URL] the edits are as follows: - Possibility to manage inventory, i.e. input the quantity available (for FlorentineShop) and the items that are not in stock should still be visible with a sign like 'temporarily unavailable/out of stock' + not possible to add it to the cart. Would be perfect to add a button for customers 'Let me know when item becomes available' and then get the customer's e-mail. - Add a tab 'News/New items' to the main menu - different news for SanLorenzo and FlorentineShop! - New items should be added to the top of the page not the bottom and possibility to change order on how they are displayed in the page; - Add banners on the page: 'Special Offers', 'News' - How to add 'Subscribe to our newsletter' link? Different links on SanLorenzo and FlorentineShop! (links from MailChimp) - Possibility to manage promo codes for check-out with Paypal (discounts, gifts, special offers) - for FlorentineShop. - Click on item opens in the same window (not new!), several separate pictures (gallery of an item), description and possibility to add to cart from the same page (where the bigger pictures are).