No, this should not prevent admission upon entry.

Unfortunately, a green card holder cannot petition for a married adult son or daughter.

You may apply under the 5-year rule and can use the Avvo search tool to find a reputable attorney.

If USCIS received the letter, you should receive acknowledgment within a month or so.

Fees vary by attorney. Consult with an attorney for guidance.

There is still 60 day flexibility for responding to RFEs.

Best have an attorney assist you. Use the Avvo search tool to find an experienced attorney.

Yes if filing under the 5 year rule.

Bring another valid form of identification at the appointment.

It does not expire unless it is otherwise revoked.