Is Canada allowed to do that? The United States wouldn't be: it's a bill of attainder.
The government donating to specific non-profits is sketchy as hell, too. Both of your solutions sounds like considerably more serious problems than Zuckerberg refusing to appear.
Even in America there has been a recent troubling trend towards Department of Justice settlements being used to direct money to specific non-profits [0]. There was an effort to outlaw these settlements but it seems to have gone nowhere.
As philwelch said elsewhere, it could be implemented as a normal tax and have much the same effect—as long as the legislation could be sufficiently narrowed to social media e.g. “sites where the content is predominantly generated by its customers.”
The government donating to specific non-profits is sketchy as hell, too. Both of your solutions sounds like considerably more serious problems than Zuckerberg refusing to appear.