Left Wing:
The durations posted are already pretty optimistic...
3 weeks for OBS is standard, 6 months to obtain your frozen ATPL, plus the rest of the technical and performance papers, and that's provided you pass them all in one sitting.
Next, approximately 10 months in Jandakot to obtain your CPL/IR, and that depends largely on weather, instructor availability, planning.... etc. Expect to stay longer if you start your course in winter.
1 month in STC for the ground school for the Learjet 45. Again, may take longer if Maroochydore cannot accept you.
Another 3 months or so for Advanced Training on the L45. That's pretty standard. The training is to give you an "intro" into airline operations, and develop multi-crew operations.
And finally, depending on when the main fleet course starts, you may have to wait a couple of weeks to begin ground school for the B777 or B744.
After that, you still have simulator and aircraft training before you become a Second Officer. And there's still another year (or so) to go before you get checked out as a First Officer.
All in all, expect to take about 3 years to become a First Officer from the time you step into SIA.
Dun think this duration is long; almost everywhere else, an aspiring airline pilot can take decades to get a FO position in a major airline. Be thankful that you have the opportunity to be sponsored and checked out in just 3 years!