There is an organization called Canadian Parents for French, which was created by the first Commissioner of Official Languages, as far as I know, Keith Spicer. He actually created this organization.
Canadian Parents for French monitors the state of French immersion across the country, but there are limits on what they do, just because of the nature of the organization. Some of the questions you're asking are probably best answered by researchers in different provinces working in collaboration with one another. Canadian Parents for French is not primarily a research organization. They are limited in what they can actually do.
In general, there is a lack of research support for this kind of effort. For example, I applied to the Social Sciences and Humanities Research Council to do research on children with reading impairment in French immersion. The grant was refused because.... It was in response to a special initiative by SSHRC for research on official languages. It was rejected, in part because they said it wasn't relevant to the mandate of the grant.
It's very hard in Canada to do research of an applied nature, because our current granting agencies support primarily theory-based research.