Add extra functionality in webshop [Wordpress]

I have a webshop in WooCommerce where I sell products. I need some extra functions in both backend and frontend. 1. Customers will make offline payments only. When he is on checkout page and presses "Pay now" button, his/her Whatsapp will open and I will receive a whatsapp message on my number with all orderdetails, like: product(s), quantity, price per product, and total order price. Then I will send him the payment details manually and he will pay it. 2. When I am logged in on admin of Wordpress and I visit my webshop, I want to see the buying-in price (purchase price) for each product. For example, If I sell shoes to my customers for 50$ and i buy them from my manufacturer for 10$, I will see 10$ on top of that product. I will enter the purchase price in admin for each product. The buying-in price/purchase price will only be visible for me (admin) when I am logged in. 3. In Woocommerce I have to give a title for each product, but instead of a title, I just want to show the brandname. I have categorized all my products on their brand, so the title should be the same as the brand.