According to the PMBOK Guide, an agile coach is a person who guides, mentors, teaches, and facilitates a team in adopting and improving agile practices and principles. The agile coach should also foster a culture of collaboration, trust, feedback, and continuous improvement within the team. When a team member is openly criticized by others during a standup meeting, the agile coach should intervene and address the situation as soon as possible. The agile coach should emphasize the ground rules of the standup meeting, such as respecting each other, being supportive, and focusing on the work. The agile coach should then redirect the attention of the team to today's activities and impediments, and help them find solutions and remove blockers.
This way, the agile coach can prevent the conflict from escalating, maintain a positive team atmosphere, and ensure the team's progress and alignment. Letting the discussion go on, addressing the team members involved during the next sprint retrospective, or avoiding the discussion by referring to the team charter are not effective ways to deal with the situation. These options may ignore, postpone, or evade the issue, which could harm the team's morale, performance, and relationships. References: PMBOK Guide, 6th edition, pages 52, 335, 540-541.

According to the PMBOK Guide, the project manager should adapt the project management approach to the development approach and the project life cycle. In a hybrid environment, where some aspects of the project are predictive and some are adaptive, the project manager should balance the level of control and flexibility, and empower the team to make decisions based on the customer feedback and the project objectives. By supporting the decisions of the team and transferring the decision making responsibility to them, the project manager can foster collaboration, innovation, and customer satisfaction. References: PMBOK Guide, 6th edition, page 19-20, section 1.2.3.2 Project Management Approaches and Development Lifecycles.

The agile leader should develop working agreements with the team to address the trouble and disputes they are facing. Working agreements are a set of guidelines or norms that the team agrees to follow to improve their collaboration, communication, and performance. They help to establish a shared understanding of the team's values, expectations, and behaviors. They also help to resolve conflicts, clarify roles and responsibilities, and foster trust and respect among the team members. Developing working agreements with the team is a participatory and iterative process that involves the input and feedback of all team members. The agile leader should facilitate this process and ensure that the working agreements are aligned with the agile principles and practices. Escalating the issue to the team's manager (option A) is not a good option, as it may undermine the team's autonomy and empowerment. Removing some of the team members (option B) is also not a good option, as it may disrupt the team's dynamics and morale. Reviewing the roles and responsibilities document (option C) is a useful step, but it may not be sufficient or effective to address the root causes of the trouble and disputes. References:
* PMBOK Guide, 6th edition, page 52, section 2.4.2 Project Team
* [Agile Practice Guide], page 27, section 3.1.2 Working Agreements
* PMP Exam Prep, 10th edition, page 465, question 465, answer and explanation

When planning a schedule with limited information, the project manager can use several techniques to identify tasks and estimate their durations:
* Rolling wave planning and an adaptive approach (A): Rolling wave planning is a form of progressive elaboration where the work to be accomplished in the near term is planned in detail, while the work in the future is planned at a higher level1. It is an iterative planning technique that allows you to plan for the future but focus on the immediate work2.
* Relative estimation to determine the task or deliverable sizes (B): Relative estimation is a technique used to estimate the size, effort, duration, or cost of work items by comparing them to other work items2. It is particularly useful when there is limited information available.
* Iterations and reviews to continuously keep adapting the plan : Iterative planning allows for adjustments and refinements as more information becomes available or circumstances change2. Regular reviews ensure that the plan remains relevant and effective.
1, 2
https://www.projectmanager.com/blog/project-management/planning-techniques-for-projects

This answer is based on the PMBOKGuide, which is one of the reference materials for the PMP exam1. According to the guide, an issue is a point or matter in question or in dispute, or a point or matter that is not settled and is under discussion or over which there are opposing views or disagreements1. Issues can arise from various sources, such as risks, changes, defects, conflicts, or assumptions1. The project manager is responsible for managing issues throughout the project life cycle, using appropriate tools and techniques, such as issue log, issue escalation, and issue resolution1. When an issue arises, the project manager should not ignore it, delay it, or inform only the sponsor, as these actions may worsen the situation and jeopardize the project objectives. Instead, the project manager should hold a meeting with the project team and relevant stakeholders to agree on the best way to manage the issue, considering the impact, urgency, and priority of the issue, as well as the available resources and alternatives1. The meeting should result in an action plan to resolve the issue, assign responsibilities, and monitor the progress and outcomes1. The meeting should also identify any lessons learned or preventive actions to avoid similar issues in the future1. References:
* PMBOKGuide