Technically speaking, none of the AR's are actually just reskins. They all have model differences in some capacity, but the fact that you have this viewpoint in my opinion speaks to the issue that I am trying to represent: Too much similarity between races. Would it make sense if instead of simply giving the Blood Elves a golden eye color option, they made an entirely new race of "Sun Elves" or whatever? It could work from a lore standpoint, as that's something entirely based on the writing and if the Sun Elves infused with Holy energy decide they don't want to live with the Blood Elves who still allow Fel energy around them, then that's something they wrote into the story. Something very dumb, I might add. Dumb because from a gameplay standpoint, you've got two different races that have the exact same aesthetic, with different eye colors.
See what I'm saying? Again it's not to say anything negative about your AR idea and how they fit in canonically, because I think it's cool AF to be honest. Orderly, zealous Orcs brought into the Alliance by the Draenei and barbaric, vengeful Humans brought into the Horde by the Forsaken. Very cool idea indeed that for the most part, works very well within the existing lore. I'd like to see what you could come up with regarding their unique customization options!