When a new stakeholder representative is introduced during a project, it is important for the project manager to engage with them directly. This allows the project manager to assess the representative's understanding of the project, clarify any concerns, and establish a communication plan that aligns with the project's existing communication management plans. Direct engagement ensures that the representative is integrated into the project's communication processes in a manner that supports the project's objectives and respects the roles and responsibilities outlined within the project team123.
Reference:
Managing Communications Effectively and Efficiently | PMI1
Communication Channels PMP: Managing Project Communications2
10 Key Project Management Communication Strategies - ClearPoint Strategy3

In a project with high uncertainty, where the customer is concerned about the number of iterations and the risk of not meeting the mandatory delivery date, a hybrid approach is recommended. This approach combines elements of both predictive and agile methodologies, allowing for flexibility in areas of high uncertainty while maintaining a level of predictability for certain aspects of the project. It enables the project team to plan parts of the project with a high degree of certainty predictively, while managing other parts with more flexibility and adaptability using agile practices.
The recommendation for a hybrid approach aligns with the guidance provided by PMI, which suggests tailoring the project management approach to fit the business environment, the risks, and the complexity of the project12. Additionally, the Professional in Business Analysis Reference Materials supports the use of a hybrid approach in situations where parts of an initiative use a predictive approach and parts use an adaptive approach3.

Effective communication is crucial for the success of virtual teams. Regularly collecting feedback from team members can help the project manager understand the effectiveness of current communication methods and identify areas for improvement. This approach aligns with PMI's emphasis on continuous engagement and iterative improvement in project management processes.
The answer is supported by PMI's resources on best practices for managing and developing virtual project teams, which suggest that understanding team dynamics and maintaining open lines of communication are essential for virtual team engagement and performance12.

project manager who is acting as a servant leader should empower the team members to conduct their job activities and hold each person accountable to improve the schedule. This is because a servant leader demonstrates commitment to serve and put other people first, and emphasizes flexibility and empathy to empower team members to adapt and thrive. A servant leader also fosters a culture of collaboration, communication, and feedback, and helps the team members develop their skills and potential. By empowering the team members, the project manager can improve their performance, motivation, and satisfaction, and ultimately get the project back on track.
The other three options are not the best actions for a servant leader to take, because:
Notifying the project sponsor that the team is underperforming and requesting additional resources to compress the schedule is a possible option, but it is not the first thing to do. The project manager should first try to address the root causes of the team's low performance, and explore other ways to improve the schedule, such as fast-tracking, crashing, or re-baselining. Requesting additional resources may not be feasible or effective, and it may also undermine the trust and confidence of the team members and the sponsor.
Contacting each team member to inform them that further schedule slips will not be tolerated by the project sponsor is a coercive and authoritarian action, which is contrary to the servant leadership style. This action may create fear, resentment, and resistance among the team members, and damage their morale and engagement. It may also increase the risk of conflicts, errors, and turnover, and worsen the project performance.
Beginning holding daily meetings to assign each team member discrete tasks with specific due dates is a micromanaging and controlling action, which is also contrary to the servant leadership style. This action may reduce the autonomy, creativity, and ownership of the team members, and make them feel disempowered and demotivated. It may also increase the workload and stress of the project manager, and hinder the team's collaboration and learning.
Reference:
Leadership Styles - BrainBOK
7 Traits of Servant Leadership in Agile Project Management - Project Management Academy Servant Leadership in PMO Management: A Path to Success - IIL Blog Project Management Institute. (2021). A Guide to the Project Management Body of Knowledge (PMBOK Guide) - Seventh Edition. Project Management Institute.
Project Management Institute. (2020). Agile Practice Guide. Project Management Institute.