The best practice in project management, as per the PMBOK Guide, involves developing a comprehensive procurement management plan. This plan should detail all the necessary procurement activities, timelines, and resources required for the project. Having the client approve this plan ensures that both the project manager and the client have a mutual understanding of the procurement timeline and deliverables, which would prevent the scenario of an unexpected contract duration discrepancy.
A Guide to the Project Management Body of Knowledge (PMBOK Guide) - Sixth Edition1.

In situations where a customer is concerned about the project timeline, it is essential to focus on delivering value efficiently. Prioritizing deliverables based on business value ensures that the most critical features are developed first. Defining frequent releases allows for quicker feedback loops and the ability to adjust priorities as needed, which can lead to a reduction in the number of iterations required to complete the product. This approach aligns with agile methodologies, which emphasize the importance of delivering valuable features quickly and continuously1.
Reference:
PMI's Practice: Iteration Planning Meeting1.
PMI's A Guide to the Project Management Body of Knowledge (PMBOK Guide)2.
PMI's The PMI Guide to Business Analysis3.

Engaging a disengaged team often involves understanding individual team members' perspectives and addressing any concerns they may have. One-to-one meetings can provide a safe space for team members to express their thoughts and feelings without the pressure of a group setting. Additionally, team-building meetings can help in building rapport, trust, and a sense of community within the team, which are essential for engagement and collaboration. This approach aligns with the PMBOK Guide's emphasis on the importance of effective team management and stakeholder engagement.
: The answer is verified and explained using the principles found in the PMBOK Guide and the Professional in Business Analysis Reference Materials provided by PMI12.

To avoid such setbacks, the project manager should have conducted a thorough stakeholder analysis as part of the initial project planning. This involves identifying all stakeholders, understanding their interests and influence, and anticipating their reactions to the project. By doing so, the project manager can engage with key stakeholders early on, address their concerns, and gain their support, which is crucial for the smooth approval of the project charter123.
Reference:
PMBOK Guide4.
Professional in Business Analysis Reference Materials5.
Project Stakeholder Management According to the PMBOK2.
Project Charter: Example, Template, Definition, & Purpose6.

Three-point estimating is a technique that can be particularly useful when there is uncertainty about the individual task estimates. It involves the development team providing optimistic, pessimistic, and most likely estimates for each task, which can then be used to calculate an expected duration for the entire project. This method is beneficial when the team lacks experience with similar projects, as it allows for a range of possible outcomes to be considered, which can lead to a more realistic and reliable estimate123.
Reference:
Expert-Guided Software Project Estimation Techniques1
Software Development Estimation: A Quick Guide - ProjectManager2
Five keys to estimating - Project Management Institute3