Hi Daniel
Here's a few things I can think of that may or may not help with your trip planning.
First up, I'd recommend snowshoes over ski options initially if you haven't had any backcountry skiing experience in your crew. My reasoning is to keep it simple at first to allow you to travel without the added hassle of skiing ability, skins and route choice while hauling packs. It's not to say you can't but from my experience using both the shoes are a great intro.
It is an essential piece of kit for everyone in the group and it is absolutely necessary to be able to travel safely in icy conditions. It may be fine soft snow on the way out but can turn bullet proof in a matter of hours and restrict all movement without some sort of traction. These and most of the gear below can be hired from a few places in Jindy. Wilderness Sports and Paddy Palin have good knowledgeable staff and can help with all your gear and more. They also offer guiding (not that you need it) along with K7 Adventures. I have no affiliation with any of them but have had pleasant dealings with all of them over the years.
Your tents will need snow pegs and they are cheap to buy. Take the best tents you have!
Sleeping mats are fairly subjective when it comes to snow so I'll start with what I use. I don't recommend it but for years I used an old (20 years old now) Thermarest Ultralite before upgrading to a Neoair directly on the snow. Most people use a closed cell and a mat of their choice on top or the best option would be a downmat. Can of worms!
Sleeping bags come from the same can. For what it's worth I started out with a 700gm bag (Paddy Freeling- had two) then a Paddy Jagungal then on to the bag I still use the most, a One Planet Custom with 1150gms down. I also own a Western Mountaineering Bison (purchased for OS trips) but rarely use it. I like warm bags as it's the one constant at the end of a hard day when I'm cold, tired, exhausted and sometimes too lazy to even cook. The body doesn't produce the heat it otherwise would so at least I'm warm. It's very hard to warm up but easy to cool down and I can bivy without a tent.
Cooking will take longer and use more fuel in general and without getting into a stove war, its personal choice. Simple answer is take more fuel and a larger pot to melt snow until you figure out the differences. Be careful taking water from any open creeks as despite people telling you they are clean... a lot of them aren't, especially around huts or common travel routes. I've been very sick and unable to move for 24 hours three days from home.
An important safety item I never leave without is a shovel. This can be hired too, and if you buy one, consider not buying one with a tiny blade. When you need to build snow walls/ shelter in a hurry the larger blades are best IMO. I have a large and small depending on the type of trip. Take more than one if you have a larger group.
Make sure you have a full waterproof shell for outerwear and the rest is up to you in terms of down jackets etc. I use full length thermals, a t-shirt, 200 weight fleece and shell. Ski gear basically. On the whole its a dry environment but I always put my sleeping bag in a garbage bag just in case as I've been known to fall in creeks or sinkholes.
Gloves should be good quality waterproof ski type and you can take an inner if you're into them.
EPIRB/PLB of course which can also be hired from NPWS in Jindy and the stores above may also hire now. I'm not a big fan of recommending GPS as your first line navigating tool but would suggest taking it for whiteout nav. (common occurrence) I haven't used mine for years but always carry it as I have every hut and major peak pre programmed in just in case.
Consider doing a shorter trip in terms of overall distance initially and spend more time getting familiar with gear and having fun doing side trips. If you leave the tent log it on the GPS and make sure it wont blow away. I've seen it happen a few times.
In terms of the forecast, my tip has always been go in on an increasing high pressure weather scenario if you're new to the game. Have a bailout option if it's trending low with gale warnings etc and go skiing or find another camping option for the weekend. It can be miserable up high but ok in the valleys so keep you're options open to base camping. Jump on ski.com.au and check the forecast page as they have daily updates provided by the BOM with snow forecast % and wind etc. The backcountry forum is also a good place to pick through info.
I'm sure there's plenty I've missed and as it comes I'll post it up. Camera and trip reports are mandatory! Be careful or you'll be hooked.....