1. Mention the number of months of the approval period of I797.
2. Address: Undertermined. City and state: Your office city and state.
I had no issue in getting stamped on using like above in my application during last 2 times stamping in Canada while the home address i mentioned is Canada.
3. It seems that this is the first time stamping at Canada location as you are asking these questions. Also there is no difference between first time and nth time or at same/different location. Just mention the detail as if its first time.
4. For not moving to US, i dont know if you can apply for H4. My attorney wont allow me to process H4 unless i am planning to move to US. Check with your immigration team on it.
5. You mean second time stamping in Canada or second time stamping for the same visa type? I assume that this is your first time stamping in Canada.
But yes, i have gone through the process stamping second time in Canada while being a commuter. Again there is no difference between first/second time at same/different location with respect to eligibility.
Not sure why you are posting in multiple threads but next time please dont post in multiple threads.