With remote connectivity, the designation of who is non-essential can change.
Back before the onset of email and the Internet, it was a task to determine who had to show up at work because of being designated as "essential staff." These personnel were aligned with the work that had been designated "essential" and needed to continue. Non-essential staff didn't have to report to work and could stay home.
For all intents and purposes these designations are now not as clear as "who is working, and who is off." In the current pandemic there has been much written about how those who have to be present to do their jobs, bus drivers, healthcare workers, meat packing workers are considered essential staff. And, is is true they are essential workers.
However, there can be another set of people who are definitely essential workers who are for instance the IT managers and technicians that allow the company or government's employees to function remotely. In most cases they won't have to report to work unless there is an equipment issue that needs to be addressed. They are essential--and working from home.
When doing your business continuity plan (BCP) or your continuity of operations plan (COOP) you will need to still designate the essential functions, but now, there are likely two classes of workers who are essential. Those who must physically come into the workplace and those who can do their essential functions from home.
A planning twist brought to you by COVID-19!