I did contact NPI as I had questions as well regarding eligibility coding. I was advised that in our case it was all code 3 except for the following:
Employees who are still serving their waiting period @ December 31st would be a code 1
All terminated employees @December 31st would be a code 1.
Still waiting for my payroll software provider (Sage 300) to provide information as to how and where to enter this data.
Hope that this helps!
In your case, HR must provide you with the data, I would send them an email requesting the necessary information so that you can do your job.