If you delete “domain-name-servers” from the dhcp request then you want to use the “prepend” line.
For best safety, I would recommend that you remove the request “domain-name-servers”.
For OpenDNS FamilyShield, he new request stanza would be:
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-search, host-name,
dhcp6.name-servers, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers,
netbios-name-servers, netbios-scope, interface-mtu,
rfc3442-classless-static-routes, ntp-servers;
And then add the “prepend” line:
prepend domain-name-servers 208.67.222.123, 208.67.220.123
Cut and paste is your friend
Once upon a time I used OpenDNS, but not lately.