I think it would be worth the money for national unity and I think it would be a useful language since it is widely spoken in parts of Europe and Africa. Why not cancel art class and replace it with something useful?Wait what?
Opportunity and mandating are two completely different things. The opportunity exists already in the form of advanced french classes. For most, it is functionally unnecessary, and bending over backwards and mandating french immersion (which would also be pretty expensive even before you get to feasibility) to appease people with extreme beliefs in Quebec sounds backwards.
There are tens of social programs I'd rather education and federal funding to go towards before mandating bilingualism.
English is an important lingua franca. /s
More seriously, learning a second language helps you understand your own language better. There's a lot of stuff about language that people just intuit in their native tongue, and never really understand.
As for how to spread bilingualism effectively, basically every single one of my male cousins and female cousin's husbands learned English from playing video games and now work as Software Engineers in Wrocław, where English is the language they use at work because there are people from all over the EU. Point is, we should give every child in Canada French language video games for free. Not edutainment stuff but stuff they'll actually play. ( I hope the kids like Ubisoft Montreal open-world games.)
This is a very good idea.