I can give you only vague generalities on the Canadian floatplane business as I'm not involved in it. However I have lived on both coasts, and floatplanes seem to be far more common on the west (Pacific) coast, than the Atlantic - perhaps because the Atlantic is much rougher, and Atlantic Canada is less wealthy, with fewer island destinations. This would mean living in British Columbia, with the major centers being Vancouver and Victoria. The good news is that you will be in the best part of the country, with a mild (by Canadian standards) climate, breathtaking scenery between the mountains and the ocean, and a very laid back attitude that an Australian will fit right in with. There's at least one scheduled float-plane operator based there.
The downside is that Vancouver is the most expensive city in the nation, and Victoria isn't far behind.
There are also floatplane operators throughout the rest of the country, mostly involved in charter services flying people into the north. Canada has a lot of north so there's a lot of these, but they are typically very small operations, and my understanding is that the pay isn't great. Pilots do it for the love of bush-flying or to build time before moving on to something with a steadier paycheque. You'll likely be living in a smaller center up north, which would be roughly comparable to somewhere in the outback, but with thirty below winters.
Maybe the coolest option would be to fly for one of the provincial fire-fighting teams in the CL-415.
Best of luck, eh!