Manage and allocate cost to each resource without HCM

Summary:

In PPM, can we manage scheduling and allocate cost to each resource from expense reports or external payroll integration without HCM?
What pre-requisites should i follow; as when creating a project based expense report following errors occur (the user is linked with person/employee in manage users option):

*The person type can't be derived because an HCM assignment doesn't exist for the person, or isn't active as of the expenditure item date. (PJC-2220072)

*Ensure that the person or assignment is active as of the expenditure item date and has a valid user person type that's mapped to the internal person type of Employee or Contingent Worker.