Ok so you are not becoming a PR, TN status is temporary. Although it can be renew a number a times it is supposed to be temporary. I know very little about the TN stuff. Some of the above will still apply, like taxes. You will file both if you earn in both countries. Your SSN and SIN cards will not be linked. Health care will depend on how long you are in the US. Since a TN is temporary that does change things.