geordieminx is right about the seat thing. Under 2 they MUST sit on your lap with the infant lap belt for take off and landing. If you buy him his own seat he can sit in that after take off, with or without a car seat. I've found that even taking a car seat they will not always allow you to use it, it must comply with the airline requirements.
Ref Emirates, don't assume you'll get the bassinet/sky cot even if you book it. When DD was a baby she flew 16 times in her first year, 12 times with Emirates and go the sky cot every time we'd booked which was great.
Last month we flew Emirates 4 times with DS who was 2 months old and despite requesting/booking/double/treble checking the skycot and having it confirmed several hundred times, we did not get it. Our first (and fourth) flight was only an hour and 15 mins so didn't complain too much about that but the other flights were long haul night flights. when we got to Dubai for them we went to double check/re-confirm as we'd been promised the seats. Basically they lied to us as said that all the seats in the bulkhead were booked by other families with infants and there just were not enough bulkhead seats. Funny old thing, on 3 of the 4 flights there NO other infants and on the one that had infants, there were only 2 where the skycots attached, and one was too big to use it. With Emirates, the baby needs to be under around 6 months (depending on weight) whereas with BA they can be much older as they have a car seat type baby seat, as well as the normal bassinet. I will never fly Emirates again.
Hope your move goes ok. Bearing in mind your long journey, I think you are making the right decision to buy him his own seat. Good luck