hello, I have 2 questions concerning 72 hours free transit without Chinese visa.

shortly I shall go from Hong Kong to North Korea via a transit of 72 hours in Beijing. I shall have my passport, a copy of e-ticket confirmed of flight to North Korea but for the North Korea visa, I shall have only a photocopy of the visa separated of the passport, that I shall received only by my chinese travel agency when I shall be in Beijing.1/ A photocopy of the North Korea entry permit is valid for the 72 hours free transit?
2/ For the flight ticket you write "seat confirmed" I suppose you will say it is the flight ticket confirmed and no the number of seat confirmed?
Thanks in advance for your answer