This appears to me to be a textbook use case for Apex-Managed Manual Sharing.
You'd use a trigger on the Account object to programmatically insert and maintain AccountShare records. The trigger would need to react to changes in the lookup field, as well as to changes of ownership (since Manual sharing records don't survive ownership changes). It'd remove ...
You should be able to use this query to find what profiles have what report permissions:
PermissionsCreateCustomizeDashboards and ...
To make it as simple (no code) as possible, you could have two custom objects, with a master-detail relationship between the two. The parent object represents the overall hiring process, and has such information as who the person being hired is, hire date, etc. The child object can represent the individual tasks that must be performed. They can be created ...
So there are a couple of different ways of being notified when an sObject (in your case User) is created in Salesforce.
Platform Events This allows you to create a Custom Event type, and then create an Event via an Apex trigger, which your third party application can subscribe to to receive these events
Change Data Capture This allows your third party ...
Welcome to SFSE.
Generally we try to avoid giving direct answers to Trailhead questions as that goes against the spirit of Trailhead. If you had something like a coding challenge and provided sample code with a specific error message we could definitely provide advice.
In the event that you did find a bug within Trailhead, we are not Trailhead technical ...
No. Related lists cannot be filtered this way. You could create a custom component or Visualforce page, or build a solution involving record types, multiple page layouts, multiple lookup fields, and a few triggers or processes.