I'd rather see Richards center the third line. Give the time Sheahan and see if he can benefit from an increased role.
As far as the D pairings go, I'm really torn. Green was pretty much delegated to a third-pairing role for the Caps, but given our depth, he's going to fill a second-pairing role. I'd love to see Kronwall-Dekeyser as the first pairing, but you'd be leaving a lot of defensive responsibility on the table with pairings like Ericsson/Smith - Green.