Hi Patty, and welcome to the forum.
I strongly support the idea of having a good plan B somewhere else in Tassie where there's not going to be snow. You may be able to make a late call if lots of snow melts (e.g. by heavy rain) and it stops snowing when predicted. There are heaps of other wonderful places to walk here.
I just spent 2 days in the Cradle area. We had snow shoes, but the snow isn't nicely packed down. I couldn't count the hundreds of times I fell through, sometimes up the top of my thigh. Sometimes I had to dig down with my ski pole to my stuck snow shoe ,nearly a metre down, unclip the snow shoe, extract my foot, then dig more to extract the snowshoe, once with my foot sitting in a previously invisible icy creek. Pretty exhausting with a 2-day pack. Would be much more exhausting with an 8 day pack. Snow shoes can be fantastic (and they were at other times), but it still took us more than 3 times as long as we would usually take to get to our destination. With bare rocks in some places, and deep snow drifts in other places, there was also the on-again-off-again snow shoe cycle, which adds more time and saps more energy. They also add a fair bit of weight to your pack for the rest of the trip.
Some folks we met (without snow shoes) were very experienced in other bushwalking contexts, and very fit, but were pretty shocked by the difficulty they faced post-holing through the snow. In the same time that would usually get them 20km, they were able to go 2.5km. And they were far more exhausted. They wisely made the decision to abort their trip and go elsewhere.
This has been a very unusual season, with more snow than many people can remember. And it's continuing, as you said. Given that, and your limited bushwalking experience, I would be leaning towards not doing the through walk this time. Do you have your own transport? That would open up lots of options. You could explore a lot more around each end of the OLT and in the middle if the weather did cooperate. Then you'd only be a day or 2 back to the car instead of a potentially impossible distance.
One option could be to start by going in to Scott Kilvert Hut at Cradle. You could get an idea of how you're going if there's still snow. if it's ok, you could go on to Waterfall Valley, with the option of continuing or completing the loop back to Dove Lake.