Yes and no.
Kul Tirans got more work done than the other allied races, that much is true, but the male skeleton resembles the vrykul skeleton. And females are built from the female human skeleton. Both are heavily modified, but not made from scratch.
Similar to how Zandalari are based on the MoP Zandalari, which were based on night elves. But with every iteration, they got more unique.
And Vulpera face animations are obviously not the same as goblins'. There may have been some work reused in either direction with the new worgen faces, but it'd be hard to tell from the final product.
I don't think the word "reskin" applies to most allied races. Dark Iron dwarves, Lightforged draenei and Highmountain tauren are reskins (and even then, they've got different features), the rest are "remodels" with varying levels of animation customization.
On topic: The word "allied race" was carefully chosen. Anything can be an allied race. Kul Tirans are a race: humans, and allied to the Alliance. Nightborne are a race: night elves, and allied to the Horde. Vulpera are a race: Vulpera, and allied to the Horde.