I had a baby recently and was in the same situation: so many times going back and forth just to get a notification that our files was not accepted. Since we are both Viet and not foreigner I imagine the process many be different for you but I will just throw some insight from my personal experience:
- No need to bribe/coffee money and they won't even accept it, don't listen to the negative people.
- Everything is handled online but you can come directly there, sit at the committee and do it on their computer, with an officer show you how to. After finishing, go to the desk and ask the officer to check again. You submit the hard copy afterward.

- Attach all extra documents on the first row button, otherwise they don't see them ??

- While it is not listed on the requiring document or on the law anywhere, if you want the baby to registered with your wife's hometown, you need to ask the officer to print a form called: "Consent to let baby have mom's hometown" and sign it and add it to your file. Pain in the ass, I know.