Both races are complete, the work is done to be a playable race.
Both have body types, hairs and other features.
At this point it would be a waist of dev time to not turn them into an Allied race.
The only question is why is blizzard not alrdy telling us they are coming?
Why do you think they keep this info for so obvious dev step.
Or will they save them and add two more and turn them into a Allied race being part of the next exp pack like we had at the end of Legion to bridge the time between the exp packs.