As I recall, the passport shall just be a photocopy (if nothing changes). They will provide you instruction to submit.
HK is a visa exempt country; however, you still require ETA to enter Canada if you are still waiting for the PR status.
The ETA can be applied online and it is valid for 5 years if approved (in experience, all my relatives visit me does not have problem to get the ETA). It is highly recommended that you print out the confirmation of the ETA (with numbers) if you need to travel by air. The Custom should be able to track your record when you arrive anyway.
Thank you So much MIcheal for your very detailed answers! I really appreciate!!