I am new to the boards and have a lot of questions.

My husband is from Canada, Quebec to be specific. Four years ago he immigrated to the US. He came here on a K-1 and we went thru all of the the correct process up to applying for AOS. We applied for that back in '04.
Just as of this week we found out we are denied, reason unknown as yet. We dont know when we were denied as there are two different dates shown, one on paper, one in their system. We have also found errors on the I-765 denial letter,(which spiked all of the following) his A number to be specific. After many calls, and a meeting with InfoPass we are no further educated on the matter than we were the beginning of this week. It has been extremely aggravating and rather stressful.
Our path now is back to Canada, where I will immigrate to.
We are currently waiting to receive the phantom I-485 denial letter in the mail.
I GREATLY appreciate any help,advice, suggestions any of you may have.
My questions are:
1. Once we actually have the denial letter in our hand and confirm he was infact denied on the date they say to be true, (9/14/07) - how much time does he have to legally stay in the states?
2. He has been out of Canada for 4+ years - does he need to re-certify?
3. Do we need to "tie loose ends" with US immigration and make it known we do not wish to go any further?
4. Should I apply INside or OUTside of Canada?Should I apply thru spouse sponsorship?How do we get our US marriage certificate Canadian certified?
5. Can I start the application process to Canada while we are finishing up w/ the US?
Ok.. those are the important basics for now.
Again, thanks so much!!!!