Yes, it is possible to allow users to login using both Single-Sign-On (SSO) and a username and password from the same application but we do reccomend one method for each user to avoid confusion. While it is generally recommended to use SSO as the primary method of authentication, there may be situations where some users cannot use SSO and need an alternative method to access their training.
External contractors or consultants may not have access to your organization's SSO system, so providing them with a separate login using a username and password could be a viable solution. These users can be set up in a different domain.
However, it's important to ensure that both authentication methods are secure and properly implemented to prevent any potential security vulnerabilities. Additionally, it's important to have clear communication with users about which authentication method they should be using, and provide instructions and guidance on how to use each method where appropriate.