Honestly a HUGE ask of yourself under test conditions to do an approach in non-radar environment if you haven't done it before. Every IFR school i've known normally does your test route as a pre test as well so that your familiar with all the procedures.
Also from BK to go all the way to TW and PMQ seems to me that the school is padding your test to make some extra $$$ when it could be done a LOT closer to Sydney. Especially if you were to stuff it up your going to spending a lot. Surely RIC or WLM would be available?
If other instructors at your school can't give you a full appreciation of what you should expect, and you haven't flown it before very hard to fly it to the standard and stress of a flightest for the first time! Personally no way i'd do a flightest in those conditions.
Anywho answer to a few of the questions
1. Not sure where you'll get handed over on that route, but your under radar control and they will hand you over whenever required.
2/3 - Read the AIPs - standard IFR radio calls to a non-radar tower. They will give you tracking depending on how you flightplan - check out the charts, you could elect to plan for joining overhead then do the backcourse, track direct to bradd, do the holding pattern there, or join on the 12 DME arc - all of this MAY depend on runway in use as well, if 12 is active it can get interesting when your trying to do an approach with ATC sequencing.
5. ATC are very clear in their instructions - but listen carefully and make sure you reply when asked too, the TW controllers can be a bit testy - but understandby, it's busy and they have no radar to keep an eye on where you are! It's too hard to say what they will tell you to do because it very much depends on runway in use and traffic around.
6. When you finally depart will again be standard IFR non-radar departure calls as per AIP and eventually TW tower will trsf you to CNTR at a certain DME depending on your crz altitude.
Big thing with TW is you never know what to expect, it all changes very quickly with runway in use - also you do need to lose a fair bit of height - your starting the approach at 5600 feet for a 1700 odd feet minima. It's certainly not one of the 'easiest' ILS's in the country thats for sure. Certainly not the cheapest either, TW council charges as well as AsA...ends up quite expensive.
Really make sure your up on your radio calls, otherwise TW tower will be ALL over you, not what you need on a test.