Monitoring Projects for No assigned or Active tasks

Need some help from the community to handle a recurring workflow situation.
The scenario is as follows:

  • Task 1 assigned to monitor completion of an activity exterior to Asana (receive payment for invoice)
  • Task 2 is dependent on completion of Task 1, but can not be assigned or due date created (create deliverable).
  • Task 3 is dependent on completion of Task 2, can be assigned, but no due date (Order Deliverable)
  • Task 4 is dependent on completion of Task 3, can not be assigned or due date created. (monitor arrival of deliverable and distribute)

Questions:

  1. How can the project manager monitor the project to determine task 1 is complete and then make assignment of task 2?
  2. How can task 2 due date be created automatically based on completion of task 1?
  3. How can task 3 assignee be notified to begin task based on task 2 be completed?
  4. If Asana can not do the above, how are project managers monitoring the projects to support this type workflow?