Hey there...my advise is that start with your PCC immediately. As you have to get it from 3 different countries, it may be time consuming. Plus the PCC is valid for a period of 12 months. As far as the meds are concerned, i dont think you will be able to get that completed unless you have lodged your application. Do get the meds done, a transaction record number (TRN) is required which is obtained only after the visa application has been lodged..cheers!!