I’m an essential employee. Does the announcement from the OA on April 3 pertain to me?

Possibly.  The need to choose between using paid leave or taking LWOP does not apply to essential employees unless you are not working a full day 7.5 or 8 hour work day or a full week 75 or 40 hour work week.  Once the POC ends, you will be required to use LWOP or paid leave to make up the difference.