I flew out of T3 last week and Fast Track was open and moving well.
There's no Terraces lounge at T3. The best bet is the new CX lounge by Gate 1 (look for the sign that says Gate 1 Lounges - it's upstairs on the second floor).
Otherwise, there's the crowded Admirals Club and not-terribly-flagship Flagship Lounge, both operated by AA.