FWIW
I did my foreign licence conversion to an Australian ATPL about 5 years ago.
Before I began I had read that some operators would not employ you if your new Australian ATPL was converted from an FAA ATP. I had a European ATPL as well as an FAA ATP so chose to convert my JAR ATPL, and avoid that potential banana skin!
Step 1: CASA evaluate your experience by validating your log books. At the same time they need to confirm the validity of the foreign licence. To do this they need permission to contact your foreign licence regulator. You will need to give them permission to release your data to CASA, and pay any necessary fees.
Step 2: CASA will write to you detailing the steps you need to take to make the conversion. Your situation sounds very similar to mine, and I was required to do a CPL air law exam, an ATPL air law exam (yes you have to do both!), you will need to do an initial medical exam, for an ATPL that will be a Class 1. Again presuming you want an ATPL then you will need to do the IREX exam, and a human factors exam. You may be still in credit on those, but I believe that there is now a 3 year limit on the written exams, only CASA will be able to confirm this. I didn't need to do an MCC course/exam. You will then need to either revalidate your MECIR or re-sit the initial. I was required to do only one non-precision approach for the issue of the licence, you may also need to do a type rating on the multi that you intend to do the test in.
if you need to do an initial MECIR then, it is possible to do the MECIR flight test in an approved simulator if you meet CASA's experienced heavy crew minimums. In my case there was no one qualified to do an initial MECIR so I ended up renting a light twin. Interestingly when I contacted the gentleman in CASA responsible for foreign licence conversions he didn't know anything about this new relief allowing experienced crew doing their MECIR tests to be allowed to do them in a simulator!
Now since then I know a lot has changed....
There is now a time limit on the validity of written exams (3 years I think!).
Australian operators are moving towards a more European style of checking and training, in that your training is tied to your training organisation (TRTO), in other words it is getting harder to arrange an examiner and a simulator to do the MECIR as an individual. You may have to go down the light aeroplane rental road if you need to re-do your MECIR.
Hope that helps