Thanks so much for the question. I agree that it's a lot to cover in a short period of time.
Canada's term of protection for copyright is based on the type of work, but for most works it generally extends, as you indicated, to 50 years after the death of the creator. The term of protection for sound recordings and performances is slightly different. It's based on the date of fixation of publication and generally lasts for 70 years after this date, so it's 70 years after the song is published. This term was changed from 50 to 70 in 2015.
There is a variety of approaches to copyright term in the international sphere. As you know, in Mexico it is life plus 100, but only for Mexican authors; it's not honoured for authors of other national origin. In the United States it is life plus 70, which is consistent with the term in Europe. There are few studies that indicate one way or the other the economic impact of the life of the creator plus 50 or of life plus 70 years, but internationally, various countries have taken differing approaches to the way they look at term.