I didnt know we can land landing in their office? I was planning to go to border as soon as I get my passport back.
For the SIN card, I can't give you a definitive answer since I'm not sure. In my opinion it should be fine.
But if you want to be sure, while waiting for other experienced user here to give the answer, what I would do is actually try to call CIC and ask for advise since you already at the end of this process.. dont forget to mention to them that you already sent the passport and just waiting it be returned from CIC.
Hope it helps! It's almost over Octanu for both of us! I'm really excited