IRS issued an FAQ on April 10 that advises us, not surprisingly, 

"Information will be provided in the near future to instruct employers how to reflect the deferred deposits and payments otherwise due on or after March 27, 2020 for the first quarter of 2020"

I think that means you'll have answers by April 29. 

I saw this coming and put off writing a couple paychecks until April 1.  Employees cooperated.

https://www.irs.gov/newsroom/deferral-of-employment-tax-deposits-and-payments-through-december-31-20...

At least people know about this.  No one is asking about the deferral of SE tax, which could be factored into the computation of 2020 estimated-tax payments.