In order for a business to receive the free 401k, do all employees need to be enrolled in payroll or health benefits or just the business owner.

For a business to receive the free 401k, all employees do not need to be enrolled in any benefit.
The free 401k is for the business, the employees may enroll or waive the benefits including 401k.
 Also note that if a employee waives group health benefits, they are still able to participate in the 401k.