A similar arrangement is in place today with Jetstar's PER-SIN service. The VH-registered aircraft arrives in SIN at dawn, does SIN-PEN-SIN and SIN-BKK-SIN (Jetstar Asia wetleases the aircraft from Jetstar Australia) then the aircraft does SIN-PER at 1735.
the SIN-MEL service will be operated as a JQ service, while the SIN-AKL service will be operated as a 3K service, since Australian carriers can't fly from SIN to NZ under the current SIN-NZ bilateral.
SIN has very attractive bilateral agreements with many countries, including unlimited 5th and 7th freedoms to and through the UK. I am sure the QF Group will exploit these rights to the fullest. They could fly SIN-STN 20 times a day if they so wished! And anywhere-in-the-UK to the USA 20 times a day too!
I wonder when countries will start to challenge the fact that Jetstar Asia is not a Singaporean carrier. Malaysia initially wanted to recognise Jetstar Asia as an Aussie carrier in the allocation of rights for SIN-KUL, but in the end after lobbying by the Singaporean authorities, they decided to recognise 3K as a Singaporean carrier.
As a Singaporean I am fine with Jetstar enhancing the connectivity through SIN as an airport, but if I were SIA I would be super pissed that the QF Group gets access to the rights that SIA has gained and fought for, for the past 3 decades. I am sure once 3K starts FCO and ATH, SQ will just withdraw!