It depends on the officers discretion. Wait for decision.

You can contact the embassy directly to request expedited processing for interview scheduling.

The country that you are physically residing at.

Best to have a consultation with an attorney to review your options.

The unmarried adult child of LPR is a faster than the US sibling processing.

No this should not impact subsequent applications.

Many documents to list. Check USCIS webpage for instructions but this is needed at time of filing.

You must file a separate I130 for your child.

Yes that is sufficient evidence that can be submitted.

NVC can take 30-90 days for review.