No, you can't bring a gun back from the US. The problem isn't on this side of the border...its the US side. In order to bring a firearm, firearm part, or firearm accessory out of the US, you would have to make an application through ITAR. In order to do that, you would have to be in the US when the application is made, and as far as I know, be there though out the processing time, until they sent back approval.

You no longer require an ATT if you have the restricted endorsement on your PAL. That being said, you can't transport restricted firearms just anywhere. They allow for transport "by a reasonably direct route" from your home, to a certified range, and back again. You can take them to a gunsmith, retailer for appraisal purposes...and I honestly can't remember all 6 conditions right now. Do a search on bill C-42. That was the parliamentary act that got rid of the need for a paper ATT.

As Kenney suggested, join a gun club. That's probably the highest concentration of hunters you're likely to find.

As for the rest of the info...sorry...I'm not going to be much help on those points.

AND....Welcome to Canada !