1, 2. To enable registration, navigate to Settings > General > Membership and mark Anyone can register, then go to Woocommerce > Settings > Accounts > Customer registration > Enable customer registration on the “My account” page.
Read more about settings – https://docs.woocommerce.com/document/configuring-woocommerce-settings/#accounts-and-privacy-settings
FaceBook and Google login – https://xstore.helpscoutdocs.com/article/87-facebook-login
Go to Theme Options > click on Publish.
3. Do you mean add them in menu? Appearance > Menus > Screen Options > enable product categories, then edit your menus.
Videos about the Header builder you can find here – https://www.youtube.com/watch?v=RbdKjQrFnO4&list=PLMqMSqDgPNmDu3kYqh-SAsfUqutW3ohlG
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.