A third-party audit provides an independent assessment of the SaaS vendor's security controls, compliance, and practices. This documentation helps verify that the vendor meets security standards and follows best practices.
Reference:
CompTIA Security+ SY0-701 Official Study Guide, Domain 5.3: "Third-party audits offer independent verification of vendor security controls." Exam Objectives 5.3: "Summarize third-party risk management concepts."

Zero Trust is a security model that assumes no trust for any entity inside or outside the network perimeter and requires continuous verification of identity and permissions. Zero Trust can provide a secure zone by isolating and protecting sensitive data and resources from unauthorized access. Zero Trust can also enforce a company-wide access control policy by applying the principle of least privilege and granular segmentation for users, devices, and applications. Zero Trust can reduce the scope of threats by preventing lateral movement and minimizing the attack surface.
Reference:
5: This source explains the concept and benefits of Zero Trust security and how it differs from traditional security models.
8: This source provides an overview of Zero Trust identity security and how it can help verify the identity and integrity of users and devices.

The first step in reducing the number of credentials each employee must maintain when using multiple SaaS applications is to select an Identity Provider (IdP). An IdP provides a centralized authentication service that supports Single Sign-On (SSO), enabling users to access multiple applications with a single set of credentials.
Enabling SAML would be part of the technical implementation but comes after selecting an IdP.
OAuth tokens are used for authorization, but selecting an IdP is the first step in managing authentication.
Password vaulting stores multiple passwords securely but doesn't reduce the need for separate logins.

Detailed Host isolation ensures that a device is separated from the network, preventing it from accessing or being accessed by other network resources. This is typically achieved by quarantining the device. Reference: CompTIA Security+ SY0-701 Study Guide, Domain 4: Security Operations, Section: "Isolation and Containment".