Pre-Hire Person type actions and Employee number assignment

We are looking at moving some of our onboarding processes to a third party, to be completed before a candidate is offically hired (they still need to pass the pre-employment physical and drug testing at this point, as well as some other processes, which may result in failure to complete the hiring process). I have been asked to investigate the implications of assigning an employee number to a pre-employee. Should we create a new "Pre-Hire" person type? Could an employee number be assigned to such a person type? Can we create a process of converting an applicant to this state