Universal containers wants to implement SAML SSO for their internal salesforce users using a third-party IDP. After some evaluation, UC decides not to set up my domain for their salesforce.org. How does that decision impact their SSO implementation?

Universal Containers (UC) has a strict requirement to authenticate users to Salesforce using their mainframe credentials. The mainframe user store cannot be accessed from a SAML provider. UC would also like to have users in Salesforce created on the fly if they provide accurate mainframe credentials.
How can the Architect meet these requirements?

After a recent audit, universal containers was advised to implement Two-factor Authentication for all of their critical systems, including salesforce. Which two actions should UC consider to meet this requirement? Choose 2 answers

A group of users try to access one of Universal Containers' Connected Apps and receive the following error message: " Failed: Not approved for access." What is the most likely cause of this issue?

Universal Containers built a custom mobile app for their field reps to create orders in Salesforce. OAuth is used for authenticating mobile users. The app is built in such a way that when a user session expires after Initial login, a new access token is obtained automatically without forcing the user to log in again. While that improved the field reps' productivity, UC realized that they need a "logout" feature.
What should the logout function perform in this scenario, where user sessions are refreshed automatically?