@Dave_Barnes, so I finally had a chance to do this today, but it didn't work. I got into Pluma, deleted the "domain-name-servers" as recommended and I added the prepend domain-name-servers 208.67.222.222, 208.67.220.220 (this is their other DNS servers besides the FamilyShield one).
I clicked on Save while in Pluma, then I exited. I rebooted then launched Firefox to test a website and it was not getting blocked. Did I miss something?
Thanks!