For your questions, after you obtain your CPL/IR, you'll spend about 3 weeks in Singapore for your L45 groundschool and Type exam. Then you'll head off to Maroochydore for your L45 Type rating... This should take approximately 2 months.
When you come back to Singapore (again), you'll be assigned to whichever fleet, either the 744 or 777. Unlikely you'll get the 345. Depending on which fleet, line training takes approximately 6-10 months, before you're checked out as a First Officer.
Of course, these timings are an approximation. Delays may occur due whatever reasons... so, don't get your hopes up too high.
Type conversion (for B744/B777) is done in Singapore, and depends very much on the simulator availability.