Lets look at the options we have for customizing Our Sign-In Page towards Microsoft Online Services, which will work very much the same as when having Federated Your users With ADFS 3.0.
I assume you have bought or started a trial of Azure AD Premium Licenses, and assigned them to the Lucky users. Now open Your Azure Active Directory Management, navigate to Configure and the green button to Customize Branding.
Smart Link or Relay State Link:
Have a look at my first: firstname.lastname@example.org