1) Could you provide us with link to your site and temporary WP Dashboard access to check and help you with this? There is no such layout by default but we’ll be able to help you by minor customization.
2) Use the Drop-down type for the cart widget in the header http://prntscr.com/ryyee4 and Ajax add to cart for simple products.
3) There is no such option, only by custom CSS. We need link to your site to give you correct custom.
4) Where exactly do you want to add such information?
