I believe this sql statement should pull the information that you want, any interfaces with 0 in and out packets in more than 3 months that are not unplugged (status 4) or shutdown (status 10)
SELECT DISTINCT n.Caption, i.InterfaceName FROM Interfaces AS i JOIN Nodes AS n ON i.NodeID = n.NodeID JOIN InterfaceTraffic_Daily AS it ON i.InterfaceID = it.InterfaceID WHERE (it.DateTime <= DATEADD(MONTH,-3,GETDATE())) AND ((i.Status != 4) OR (i.Status != 10)) AND ((it.In_TotalPkts = 0) AND (it.Out_TotalPkts = 0)) GROUP BY n.Caption, i.InterfaceName
-EDIT-
although i just realized that i missed the last line of your message about what you ideally would like to see but they could be added in in the select portion