even though, my kids are Canadian.... they have to pay for International's tuition fee (because parents are not in Canada with them and they are not born in Canada)
Do you have detail information of this new arrangement? I cannot find any indication of "immigration applicant" can pay "local fees" in universities website.
I would think you are talking about university education, since primary and secondary education are free to canadians and thus there is no such thing as 減至當地學生水平.
A typical university tuition policy would be that, you need to be a (1) canadian (i.e. with canadian passport) or (2) permanent resident to qualify to pay the "local fees".
To qualify to be called a "permanent resident", you need to have been granted permission to live and stay in canada with no time limit. A visa student is not a permanent resident. Most of the time, only landed immigrants (i.e. immigration application approved and have official "landed", but not yet obtained canadian citizenship status) can enjoy this benefit.
But of course, each university can give different kinds of offer to students. May be some less popular universities in remote or underpopulated province have policy that are a lot more lax.