Yes you can use the I94 from online.

Best to have an attorney review the nature of denial to determine next best steps.

Best to have an attorney review the basis for denial to discuss next best steps.

Yes you may marry and begin the process for your green card.

Best to file by paper and indicate this by hand.

Yes, the police report is not needed if pre-age 16.

Yes, you may apply for another I 130 at this time.

You may indicate unknown information or refer to your mother’s naturalization certificate.

That is not a basis to expedite. It can take 2-6 months post notice of interview scheduling.

Depends on the consulates availability.