EDIT:
I did not put speculation in the title, and since several people have taken offense to my wording apparently, I've asked for the title to be changed as I found no means to do so myself. But please, refrain from attacking me as a person due to my wording all the same. It's not really the point of the thread and pointless behaviour.
What I've provided is evidence that proves that Vulpera shares some things in common with other allied races, and a video of very detailed customization options, like for example, noses. Pointlessly minute things to work on for a NPC race.
The reason my original title has the words "low-key confirmed" in them, is simply me saying, all the evidence points to this being a confirmed thing we're getting. I wouldn't have used the prefix of "low-key" otherwise.
/EDIT.
https://twitter.com/WowChakra/status/960999877516947456
See those numbers at the end? That is the allied race variable, see how its exactly the same for Zandalari and Vulpera? So yes, they are being added and yes they are going to be Horde. They even added child models to them with this patch.
Unless their catagorization on the client changes, they are indeed flagged as an allied race.
And you can see that the kul'tiran humans and several other NPC races are in here, however they do NOT have the allied race variable on them, and there are two different variables, one for alliance and one for horde.
So there you go, argument is closed unless this variable changes.
Edit: More Evidence in the fact that their customization options are extremely detailed, there is even nose options.