The GC will be mailed upon entry into the United States.

Yes the 2nd and 3rd most recent years are required.

You can update this at time of interview without issue.

This would be best answered with an attorney during a consultation.

She may be adjustment eligible after 90 days of her entry into the U.S.

It is important that you marry for organic reasons, not for immigration related benefits. Consult with an attorney for guidance.

After 90 days of her entry, she would be eligible for adjustment of status in the U.S. Consult with an attorney for guidance.

Write to the Consulate directly to inquire about the status.

A review of your case is needed for most appropriate guidance.

It should be based on your birth certificate.