Ref: https://docs.oracle.com/en/cloud/saas/project-portfolio-management/19a/oapem/execute-project-tasks-and-deliverables.html#OAPEM1122082 Followers are persons who aren't working on the task but have an interest in reviewing the task progress. Only the resources and other followers can add followers to a task. If a resource assigns the task to another team member, the application automatically changes the original resource to a follower.
What's the difference between my tasks and tasks that I follow?
You can edit task details and enter progress for your tasks on the Manage Tasks page. If a task has multiple resources, only the primary resource can edit the task.
When you follow a task, you can view the task details and see the task activity stream. You receive e-mail notifications of changes that team members make to the task.
If a resource reassigns the task to another team member, then the previous resource automatically becomes a follower.

The Allow Override option for the Default Capitalized Interest Rate Schedule is specified on the Manage Project Type page. This option allows you to override the default capitalized interest rate schedule for a project or task that uses the project type. The default capitalized interest rate schedule is used to calculate the capitalized interest amount for a project or task based on the interest rates and dates defined in the schedule. Reference: https://docs.oracle.com/en/cloud/saas/project-portfolio-management/20c/oapfm/manage-project-costs.html#OAPFM2356031

The recommendation for this scenario is to define one business unit and two project units. A business unit is an organization that performs one or many business functions such as transaction processing or reporting. A project unit is an organization that manages projects within a business unit or across multiple business units. By defining one business unit and two project units, you can meet the following requirements of the client organization:
The management reporting and transaction processing requirements are the same for both the organizations: This can be achieved by using the same business unit for both the organizations, as the business unit determines the common setups such as ledger, currency, calendar, etc. for transaction processing and reporting.
The project planning, management, analysis and reporting requirements are different for each organization: This can be achieved by using different project units for each organization, as the project unit determines the specific setups such as project types, templates, options, etc. for project planning, management, analysis and reporting. Defining two business units and two project units is not recommended for this scenario, as this would create unnecessary duplication of setups for transaction processing

Ref: https://docs.oracle.com/en/cloud/saas/project-portfolio-management/19b/oapfm/project-costing-configuration-define-project-costing-integrations.html#OAPFM3094605 Topic - Deriving Projects-Related Accounts

Authorization Policy Manager (APM)
APM greatly simplifies the creation, configuration, and administration of application policies APM does not support the management of users and external roles; these artifacts can only be viewed with the tool. Their provision and management is typically accomplished using Oracle Identity Manager Oracle Identity Manager (OIM) In regard to enterprise users and external roles, Authorization Policy Manager provides viewing and searching functionality only. To manage users and external roles, use Oracle Identity Manager or some other identity management tool.
OIM provision users, roles, and defines what a user can do in Oracle Cloud Duty Roles are mapped to jobs and assigned access privileges (Data Security)