USCIS can make corrections to your birth certificate with supporting documents.

It depends on your immigration status. In general, Canadians require only a passport for US entry.

According to your statement, parents " will be living there for a while", then residence is Australia.

Your diligent research may find a trusted charity for assistance.

The reviewing officer has a lot of review to do, i.e 2 I=751 denials and a pending I-751. It takes additional time to make a decision. By...

In your case traveling abroad results in abandonment of pending A/P Applicaiton.

Yes, to apply for IV you need to demonstrate unusual/extreme hardship to a qualifying relative. Consult with an attorney for further guidance and...

Yes, you may with supporting documentation.

It appears the question or substantially similar question has been answered.

I see no reason to reject an offer by A and wait for an offer that may never come from B.