CX never had a lounge - they used DNATA
The SATs lounge isn't bad, especially if you've just got a short while. Otherwise it's pretty doable to use the QF or BA lounge (why not both...they are next to eachother) but note that they'll close once the operating carrier flights have left around 11pm (if you are on the 2am flight)
As an aside QR are moving to T1 on the 28th October - their 9.20pm flight actually slots in nicely to be able to use the BA lounge at a quieter time, will be closed for the other two so presumably they'll use a contract lounge officially though