Yes if they were lawfully admitted to the US they may apply for adjustment of status.

Refer to the direct filing address on USCIS webpage.

Likely a few weeks to month after that status.

You should consult and work with an attorney right away to determine next best steps. Good luck.

Refer to the USCIS processing page for specific guidance.

Best to consult with an attorney about possibility of late marriage post 90 days entry.

Did you properly submit all documents? Consult with an attorney for review of documents.

Contact USCIS to inquire about specific service center handling the I130.

Inform the officer at time of interview and should not be an issue.

You would fall under country of birth category.