关于去美墨旅游证件问题

Thinking take a vacation, either DRIVE to Toronto, Cananda, or FLY to Cancun, Mexico.  Questions:

1. I have Green Card, do I still need visa to visit either place?

2. My wife is US citizen, does she still need visa to visit either place

3. 2-yr or younger kids, born in US.  Do they need passports or birth cirtificate is good enough?

4. Parents from China, with US B-2 visa.  I assume they need visa from Canada or Mexico in order to cross the border?  anyone can confirm?

thanks!