Yes, you are able to have a mixture of Email-based & Federated users.

However, the Email-based users need to use a different domain for their email address from that used by the Federated users to make sure users don't get caught with the single sign-on page. 

For more information on Email-based and Federated users, please refer to articles:

• How to add Email-based users
• How to add Federated users