A customer reviewed the plan for a project with high uncertainty. The customer expressed concerned about the work requiring SO many iterations with a risk of not reaching the mandatory delivery date.
Which approach should the project manager use in this situation?

A project is in the execution phase. The client was actively involved in the early stages but has been less engaged lately. A number of changes to the requirements have recently been requested.
What should the project manager do next?

A project manager notices that a new junior team member's suggestions are constantly rejected by senior team members. The senior team members find the suggestions valid and innovative, but unrealistic. Following several project assignments, the senior members request to have the junior team member removed.
What should the project manager do next?

A project manager is assigned to a multiyear project. During project execution, the customer delegates a new representative who contacts the project manager directly with a concern about their participation in status meetings. The representative wants to contact team members directly.
What should the project manager do next?

A project manager has been assigned to a new project that will be delivered using an agile framework. The sponsor is asking for a cost estimation to build the business case.
What should the project manager do?