Requirements for Long Term Part Time Employees

Does a safe harbor plan with less than 100 employees need to give the safe harbor match (or non-elective) contribution to these Part Time employees now eligible to participate?

The plan must provide that LTPT employees have the opportunity to make elective deferrals.  Anything beyond this is optional. 

The number of employees is not a consideration.  

The plan is not required to give LTPT employees the safe harbor match or non-elective contribution.

As Paul says, optional, not required. But track your elections so you can incorporate them into the plan document. Or if you've already executed your SECURE Amendment, make sure it does what you want it to do.