Personally, I use option number 3, swapping SIM cards on an unlocked phone. Please note that your home provider may give away your number if you are gone more than three months. But these days when no one really memorizes your number anyway this is not a liability.
Unlock your phone before leaving the country. Keep your Canadian SIM card just in case your number is not reallocated. Just note that provider loyalty is a thing of the past because when you return you can shop around for the best deal with an unlocked phone!
And it’s really, really handy to have a local number wherever you are living internationally. Not to mention much cheaper (than Canada, for sure!)