I didn't really count, but I know when I got it.
Across 3 accounts(one is my daughters). 9 Alliance able to do it, and 5 Horde, so 14 total characters. My lowest still able to do the quest was 81, my next is 69 and was not able to get it.
Day 5 I got it on the 3rd character.
so... accessing brain information... 59th opened package. 14 x 4 = 56 + 3 = 59
I have done it a total of 6 days and so far just the one so far. Still trying to get one more for my daughter.
Also I missed a few days due to not knowing it would drop from the Quest, I read somewhere (probably wowhead) that it was going to be in a present during the opening of the presents part of the event. I have received three Lumps of Coal, one round "football", and one of the ilvl 480 daggers.