One-off individual legendaries have not necessarily been earn-able right away as appearances. We know that the sets are really cool and we do have plans to allow players to earn the entire appearance set in Shadowlands. But from the outset, the legendaries are just one-off pieces that you can wear and not mog over if you want to do that. We do want to make sure that you're crafting your legendaries because those are the powers you want and that's whats complimenting your set as opposed to feeling like if you wanted to collect the whole outfit, you needed to specifically make all of these different slots even if you had no intention of using them as real pieces.

Would there be a chance that the other datamined legendary tints would be available in a future patch?
That seems likely. We know that they're a really cool set and we want to get them in players' hands. As we learn more of the Maw's secrets, and the power that went into making these items, we'll probably have more opportunities to access things like that.
https://www.wowhead.com/news=319240/...ppearance-set-

I seriously want that green cloth tint.