Universal Containers (UC) has built a custom token-based Two-factor authentication (2FA) system for their existing on-premise applications. They are now implementing Salesforce and would like to enable a Two-factor login process for it, as well. What is the recommended solution as Architect should consider?

Universal Containers (UC) has a mobile application for its employees that uses data from Salesforce as well as uses Salesforce for authentication purposes. UC wants its mobile users to only enter their credentials the first time they run the app. The application has been live for a little over 6 months, and all of the users who were a part of the initial launch are complaining that they have to re-authenticate. UC has also recently changed the URI Scheme associated with the mobile app.
What should the Architect at UC first investigate?

Universal containers (UC) has implemented ansp-Initiated SAML flow between an external IDP and salesforce. A user at UC is attempting to login to salesforce1 for the first time and is being prompted for salesforce credentials instead of being shown the IDP login page. What is the likely cause of the issue?

Universal Containers wants to secure its Salesforce APIs by using an existing Security Assertion Markup Language (SAML) configuration supports the company's single sign-on process to Salesforce, Which Salesforce OAuth authorization flow should be used?

Universal Containers (UC) uses an internal company portal for their employees to collaborate. UC decides to use Salesforce Ideas and provide the ability for employees to post ideas from the company portal. They use SAML-based SSO to get into the Company portal and would like to leverage it to access Salesforce.
Most of the users don't exist in Salesforce and they would like the user records created in Salesforce Communities the first time they try to access Salesforce.
What recommendation should an Architect make to meet this requirement?