"We are all Canadian."
Emphasis and it sounds better. Just like the "all" in the English translation.
Because 都 is the modifier of 我们， not of 加 拿 大，so it needs to be placed near 我们 in the sentence. It's like saying "we all are Canadian" rather than "we are Canadian and..."
Is there a way to use 都 so that it unambiguously means "both" instead of "all"? Or does it just depend on context?
Contect. 都 means "all." If there are only 2 people involved, than "all"="both".
The correction says I used the wrong word. It was all correct words. The word shi meaning is was omitted however the word shi is often omitted by Chinese people talking to me. I guess it is a lazy or slang word to omit in a conversation.