You can do a 150 hr CPL if you wish. It just means that your hours may not count towards meeting any of the 150 hr syllabus requirements. No benefit to you with your hours but should you choose...
All your hours count towards meeting the 200 hr CPL. You may still need to do more than the 200 hour minimum though if your hours fall short somewhere. For example, one of the requirements is to have 100 hrs command. If you somehow managed to accrue only 50 hrs command within your current 160 hours you would have to do at least another 50 hrs command + whatever other training is needed, even though you reached 200 hrs total.
There is no requirement to hold a NVFR or IR for an Oz CPL to be issued. However you need to gain at least 40 hours so it would be sensible to dedicate any leftover hours towards the next rating if you reach CPL standard in under 40 hrs.