To hide highly sensitive Life Events or Business Milestones until they happen, the Admin can hide them on the Events & Business Milestones Lightning Component page properties. The Events & Business Milestones Lightning Component is a component that displays a timeline of life events and business milestones for a client or a group. The Admin can use the page properties to customize the component and select which event types or milestone types to show or hide on the timeline2. Verified Reference: 2

Explanation
The following things must be kept in mind when creating Action Plan Templates:
When creating Action Plan Templates with the UI, you can designate a plan owner different from the plan creator. The plan owner is the user who is responsible for executing the tasks in the Action Plan.
The plan creator is the user who creates the Action Plan Template or the Action Plan from the template.
You can assign a different plan owner for each Action Plan Template or Action Plan.
An Action Plan is a run-time instance of the template that allows you to automate the sequence of the tasks you defined in the template. An Action Plan Template is a reusable blueprint that defines the tasks, owners, and deadlines for a common business process or service request. An Action Plan is a specific implementation of the template that applies to a particular target record, such as an account, contact, or opportunity.
When you create an Action Plan from a template for a specific target record, item deadlines are calculated using the start date and date offset defined in the Action Plan Template. The start date is the date when you create the Action Plan from the template. The date offset is the number of days before or after the start date when each task is due. You can specify different date offsets for each task in the template. Verified References: : Salesforce Help Article 2 : Salesforce Help Article 3 : Salesforce Help Article 4

Explanation
To update an existing, published Action Plan Template, the Admin should clone the existing Action Plan Template and make any necessary changes on the new Action Plan Template. This is because published Action Plan Templates cannot be edited directly or set to inactive4. Cloning an Action Plan Template creates a copy of it with a new name and ID, which can then be modified and published4. Verified References: 4