The "Retesting" phase in the bug life cycle is when a specific defect or bug has been fixed and is tested to ensure its rectification. It's a verification process to confirm that the particular defect has been successfully addressed.

Incremental Integration testing involves testing parts of a system sequentially as they're developed. In environments where multiple teams work on different components, this approach ensures that each new piece integrates smoothly with the existing parts, helping detect issues early and reducing integration risks.

A Walkthrough is a type of review where the author leads members of the review through the document based on their understanding. It's informal in nature and often relies on scenarios to provide the reviewers with a deeper understanding. The main goal is to gather feedback and achieve a common understanding.

Configuration Auditing is a critical aspect of Configuration Management. It involves the process of evaluating and examining the configurations to ensure that they align with the approved configuration documentation. Through this, unauthorized changes, discrepancies, or inconsistencies can be detected and addressed promptly.

Requirement-based Testing, as the name implies, involves designing test cases directly based on the system requirements. It ensures that the software system meets and conforms to the specified requirements, making certain that all functionalities are tested as intended.

If a defect is considered not genuine or if it's not a real issue, it is typically marked as "Rejected." This status indicates that the defect raised is either not replicable, is intended behavior, or isn't valid in the context it was reported.

Alpha Testing is usually performed in a controlled environment and involves internal teams. This allows the organization to receive feedback in a quicker and more direct manner. Beta Testing, on the other hand, involves actual users but may introduce challenges in managing feedback and potential public relations issues.

Accessibility testing primarily aims to ensure that applications and websites are usable by people with disabilities like visual, auditory, cognitive, and motor impairments. While usability, compatibility, and performance are important, they are separate areas of testing. Accessibility testing focuses on ensuring equal access and inclusivity.

The Agile model is well-suited for projects where rapid changes are expected, as it emphasizes adaptability and customer feedback. Iterative development allows the team to accommodate changes in requirements and design more flexibly than traditional models like Waterfall or V-Model.

Configuration Management (CM) in software development primarily serves to systematically manage, organize, and control the changes and versions in software documents, code, and other entities during the development process. It ensures consistency and traceability across the software lifecycle.