I know that in Mexico, gun ownership is either extremely strict or completely illegal. I think you can own and carry in Brazil if you are licenced, im not sure on that, I would have to look into that further. As for the other countries there, I do not know. There are other countries with good gun laws, such as America, Canada, switzland, and one or two east european countries. How come you are interested in the mid and south American region?
Honestly, Canada's laws aren't that great. Semi auto rifles restricted to 5 rounds, certain "assault rifles" banned, need permission from police to transport firearms from one place to another (Authorize to transport), 28 day waiting period, minimum barrel length and capacity for pistols.
You can argue that they are the same as Australia's, except semi auto rifles/shotguns and pump action shotguns are legal.
Here is a link btw... http://panda.com/canadaguns/