I am not too sure about this.
But from what I think, you would need to have CITIES even if you are bringing it in to the States and back to Canada again. I mean they wont know if you traded a ball python or something during your stay in the states right? Getting the permit can take quite long. Something like 3 months+
not too sure on this one but should be something like that
maybe others with more info on Balls could help you on this one~