With an IP address from CenturyLink, the WAN side of the house is all set. IP address from CenturyLink is the critical piece.
With PPPoE, pfSense does not report connection speed or duplex.
Make sure the PPPoE Gateway is set as the Default Gateway (System>Routing, see image below). You might also want to add the CenturyLink DNS servers to your DNS list (System>General>DNS servers, see image below).
As for the LAN side, most likely a firewall issue or route issue. Make sure you are not blocking routes to the WAN from LAN (see image below). Just to verify, take a look at Diagnostics>Routes to see if LAN can route to WAN.
Last one, in researching the speed issue with pfSense and gigabit PPPoE connections, I opened a support ticket with pfSense. As of v2.2.3, pfSense will not attain gigabit speeds with PPPoE (https://redmine.pfsense.org/issues/4821