Some things to keep in mind when looking for bush/float jobs are:
1) Most will require at least 250hrs on float
2) With 300hrs, I think you'll find you are offered a position as a dock hand for 6-12months before being offered a flying position.
3) However, from my understanding, once you DO get that flying position, you will log a high number of hours in a season.
4) Best time to look for float is late Winter and early Spring.
5) Keep in mind... the new insurance premiums have been or are being released shortly which will push up the required total time minimums for Pilots.
6) Re: Aussies and Kiwis, I THINK you may find they are here on the one year working visa they are entitled to as we are for going to their country. Some operators may extend those visa allowing them to continue working. However, having worked with Canadian Immigration years ago, you would be hard up to find many foreign pilots that moved here with the intention of gaining permanent residency without a job, especially low hour pilots. It just doesn't happen. As much as Canada lets in foreign immigrants - if you're not an asylum seeker or refugee, you're not going to have much luck getting in without meeting the "points" requirements for immigration.
So, I hope that helps you out a bit.
YYZDUB