1. I can ask my aunt for the birth affidavit and noterized. However, if my aunt not 100% can read english affidavit. Do I need to prepare both english and chinese( translated from english) for her to sign? Or, english affidavit is good enough and we can just explain to her if she doesn't get some meaning of it.
-Your aunt can write it in Chinese with her signature (notarize her signature), and then ask your friend to translate it into English following the USCIS translation requirements and natarize the translator's signature. See this link for more information:
Information about Translating Foreign Documents
2. Do I need to get a proof for mom that the 'primary document is unavailible",
Yes. If you have a relative in your mother's home town, you may ask him/her to ask the local civil department （民政部門）or local police department (派出所）to issue a 證明 addressing that your mother moved out of her home town to Hongkong at very young age and then, immigrate to Canada and never returned to live in her home town, so her birth record was lost and not available anymore. Then, ask your friend to translate it into English as addressed above.
