The 16 Bi$ figure is for 36 aircrafts (including the 16 options) and means a price per unit of 445 Mi$. This is exactly the unit cost listed on Wikipedia. So we can assume the real price for the contract is lower.
Very much so. Common discounts for airframes can be 40-50%. Given the circumstances I'd assume Emirates got somewhere near 50; who knows. But both parties needed this deal and as other comments correctly point out the unusually public manoeuvring has been going on for months.
Of course, no-one in the media has any idea about this very closely guarded commercial information and so they simply go by the list price.