Thank you for posting here in the Community. I can provide some information about adding an employee in QuickBooks Online Advanced Payroll.
Yes, it's possible to add a worker without the information you mention above. If the National Insurance (NI) number for the employee is not available (or the employee is exempt from supplying a NI number), click the 'NIN unknown' box.
On the left navigation bar, click Payroll.
Click Add Employee.
Fill in the necessary information.
Under Tax and NIDetails, search for the National Insurance Number field.
Put a checkmark on the box beside NIN unknown (NINO).