Usually, for the name attribute, to a new signed up user, unless an action or an additional sign up field is used to assign a custom value to the attribute through an action or other methods, it will contain the email address of the user.
For the given_name or family_name user attributes, unless they are also populated through a form, action or custom sign-up field, they will be missing from the overall RAW JSON of the user.
If you are migrating a user through an enterprise connection such as Okta Workforce, their First Name and Last Name profile attributes will be assigned to the Auth0 user through user mapping if specified, if not, they will remain also empty.
If you have any other questions, feel free to leave a reply!