Those races sadly won’t be coming. Did you notice that while Dracthyr have a new skeleton, they deliberately cannot wear armour unless using a visage form and those visage forms are based on existing models?
We got the explanation. A player race needs to use a skeleton on which the model can be built. Player skeletons are vastly more complex than NPC skeletons. It is a permanent commitment of time as every single piece of armor in the game from here till shutdown will have to be tested to see that it fits. Each new race means that process takes longer. It is why they have defaulted to adding new races with existing skeletons (Haronir are the third use of the Night Elf skeleton now).
They may introduce a new skeleton race at some point in the future but anything that would require a new skeleton is pretty much at a disadvantage when it comes to choose.