Hi paala
there are bit less chance of approval of student visa as they can refuse for the of genuine temporary entrance. U can still try that if you want. On the other hand, u can let your employer withdraw nomination and let ur visa refused. By this way, at least u can apply aat, federal circuit court and federal court. From here you can buy plenty of time to think about something else. Unfortunately, when immi will refuse your application, u will be barred from lodging most of the applications onshore in future. So what u have to do is to get bridging visa b, go offshore to lodge any application and come back(u can come back only for permanent visa application such as 187, 190 otherwise u have to stay offshore till decision for rest of the application eg 457, student)
i hope this will help u