As far as I know the First Class lounge at AUH T3 is closed since August, and will remain closed for a while (some say re-opening could coincide with December launch of A380 to LHR).
In the meantime the new Business Class lounge at T3 (renamed Premium Lounge for the sake of obfuscation) is opened since end of August and has large seating capacity + 3 buffets & bars.