Easyrsa for pfSense & webGUI
I have already setup my CA and began issuing client certificates, now that the CA has been establish can I use Easyrsa for pfSense to manage the certificates and the DB without creating a new CA?
Not easily, no. EasyRSA wants to create and do everything itself.
I suppose if you very carefully exported the CA from pfSense and set all of the files just right (e.g. serial.txt) it might come out OK but it's still not something I'd recommend.
Why would you want to use EasyRSA to manage certificates instead of the GUI?