Is Ctrip Booking confirmation with ticket number enough?

Hi. My daughter is visiting us in Shanghai next month. We will fly off to Vietnam for a few days with China Eastern, and I booked the flights through Ctrip. I tried to get the full ticket details from China Eastern website but cannot. I have the full CTrip booking confirmation with ticket number, my daughter's details etc. Is this enough, or do I need the China Eastern one? Also - does "Confirmed seat" mean that the actual seat number needs to be on the booking, as I don't think the seat is confirmed until check in. Many thanks for any help.