This requires that you earn your income through a company under your control and that you can pay to setup a complicated tax avoidance scheme like that, and pay

This requires that you earn your income through a company under your control and that you can pay to setup a complicated tax avoidance scheme like that, and pay to defend it, and even then you may get it wrong and end up paying taxes and penalties. I don't recommend trying things like this. In this specific case I guess you'd make your money from the IP royalties in Costa Rica, so it may avoid the Canadian source income. I doubt it would stand up to scrutiny though, the courts would very likely see right through it.