Here's my whole analysis that makes me think it's fake and probably from a Scalie server. My sister, who is an artist (though not a 3d artist) also helped with her eye for design.
Firstly, and most damningly, is exhibit #1—I am 100% sure this is actually a
preexisting mesh applied to the body meant for a type of armor. How WoW used to do some armors (and still does for a few) is that they would actually make a new mesh for the underlying model. I think this was either accidentally or intentionally toggled for whatever reason—I think there's actually a Legion armor (for Mages IIRC) with "shorts", and the "shorts" over the legs were probably what was specifically toggled, because it reminds me of them. I don't recall which one, though. I think it might've been Nightborne-adjacent leveling gear, though. Exhibit #1 is the most awkward mistake I've seen on this model, which is surprising for being such a small one. I simply cannot explain it away.
Exhibit #2 has been done to death—the "nipples" people are seeing are the wings, which are an adjacent mesh that doesn't connect to the body as a whole (whereas I'd expect Blizzard to build the wings entirely into the model instead of using them as an attached mesh like eyes and Elven ears are, since they're probably neither separately attached to permit for easier customization (like hair, beards or eyes) nor need to be removed for some armor types like most mesh parts. This is pretty awkward to me, and it almost certainly confirms this can't be Blizzard because it's such an awkward, obvious and somewhat explicit mistake to make.
Exhibit #3 is the awkward horns that seem to have a metallic or crystalline texture—admittedly, it would look really pretty on a Blue Dragon specifically, since they are known to have crystalline growths sometimes, but it looks super awkward on this model. It is golden, too, so it doesn't match up with any preexisting flight. If they were purple, then this would actually
give points to the leak because it would seem absolutely suitable for something related to Blue Dragons, since Senegos already has those kinds of growths. However, it's also awkward they don't appear in place of the chin spines (though they could just be a different customization option that allows them to be crystalline separately from the horns). It does seem like the crystalline horns are a customization option, since I think they're not on the red one we see in the other screenshot.
Exhibit #4 was pointed out by my sister, who noted that the heads are also smaller than most WoW model heads. I agree—this is one of the things that makes me think it's a Scalie model, along with the general softness and femininity of the face. The weird, angular eyes and the "eyelashes" really make me feel suspicious. The fact that the heads are smaller also makes it hard to believe this is a WoW model, since the heads are so often very large on Blizzard models.
Exhibit #5 is the translucent wings. They were mentioned by the leaker, but the way they work is a little awkward. It is possible the leaker noticed them but couldn't do anything about them, so he just added that to obfuscate them as a mistake or a weird design choice.
Exhibit #6 is that the feet look more like Worgen feet than, say, Sethrak or actual Dragon feet. My sister said that she's pretty sure it's not the same as the Worgen feet due to a larger lifted claw and there being three toes + dewclaw as opposed to four + dewclaw on the Worgen model, but I think it was based on them.
Exhibit #7 is the awkward texture shift. Most of the textures in the game are a little more subtle than this, whereas the textures shift very dramatically here and look a little inconsistent. The incongruity is damning. This was also pointed out by my sister. My sister also noted incongruous color shifts, but I don't really see it that much. She says it does look like a detail a Scalie who intends for them to wear minimal armor would add, but not the WoW team.
Exhibit #8 is that they also just seem to have breasts due to the way the model is made. It looks very awkward, and they're both awkward and unwieldy and far too large to be WoW breasts. It also is odd they have them on Lizards. This does look very slightly like it may have been based on the Arakkoa's body shape, but they don't have it so horizontal. This definitely feels like a Scalie addition.
Exhibit #9 is that the wingtips look a little awkward to me—they actually look quite a lot like WoW's Dragon models, but they also do seem like they may have had some copy/pasting going on. They just look off to me—they actually seem a little low-resolution, too. They may be partially copy/pasted, which also could explain why the wings as a whole are iffy.
If they are meant to wear armor, the spikes on the shoulders are also very awkward, though I also think they are the most Blizzard-like design of the whole model.