Originally Posted by
pacotaco
Let's make this easy for all this people that have a hard time to understand the weid chronology of WoW:
All DKs start at the prelude of WotLK (year 27). Worgen DKs are Arugal's, and goblin are Steamwheedle.
All DH start at the prelude of Dark Temple (late year 26).
Draenei and Blood Elves start at the prelude of the Burning Crusade (early year 26).
Humans, Dwarves, Night Elves, Gnomes, Gilnean Worgen, Orcs, Forsaken, Tauren, Trolls and Bilgewater Goblin start at the aftermath of the Cataclysm (year 28)
Pandaren start between the Cataclysm and the prelude of MoP (years 28-30)
Now, the new allied races are implied to start the moment we unlock them, so that is after Antorus raid: year 32+.
So no, the new races can't be DKs because they were isolated at the year 27 (5 years ago). Maybe Dark Iron and Zandalari could be. I can also see Pandaren (lore-wise it's possible).
They can't be DH either for the same reasons.
The rests I asume they're recently trained people, so they could be any of the non-hero clases (but I understand the restrictions bases on race identity).