Adding certain items on checkout, homepage

I'm looking to add certain features to my wordpress site. I'm currently using the superstore theme from woocommerce. Items that I need for my website: -I want to add a feature at checkout/cart where a customer can add a tip to the total. -I also want to add a feature at checkout where the customer chooses a predetermined delivery location from a drop down (required filed). -I want to add a welcome page similar to [login to view URL], [login to view URL], [login to view URL] where it requires the user to register or login before entering the main site. -I also want a feature where the customer can request an item that my online store does not have and also have a feature where they can substitute and item if that item is out of stock. I know this doesn't require complicated code but unfortunately I'm just a novice with wordpress. Please message me if you have any questions. Thank you