Custom changes to WooCommerce

Hello We have a WooCommerce site based on Nitro theme. We need 3 customizations: 1. We are interested in enabling our customers to edit their orders once it is complete. They will edit only some fields, for example their billing details, and they have to edit some custom fields as well, for example their VAT number. You must enable the customer to change their fields on every order after the order is made. The reason for this is that the customer might not fill out the fields correctly when making the order. We will then give the customer a chance to update their information AFTER the order has been made. 2. We need to sync the changes the customers make to our CRM system. We have an API expert for our CRM, but we need help with the WooCommerce API connection. We will sync whenever some changes are made. Some fields might not be a part of the WooCommerce API. You must help us sync them. 3. We would like a correspondence section on each order page where the customer can interact with a support representative (an admin user). It will work like a chat-support section. Users can start a new coversation on this page, and he can reply to existing conversations. All will be shown on the same page. This conversation is to establish a place where customer and seller can communicate after the order has been made. If you have any questions kindly ask them precisely. Messages about "chatting more" or "talk more" will be reported as they are unacceptable and helpful.