Artifact skin unlocks: unique vs. character-wide vs. account-wide?

While checking out the artifact calculator on wowhead and the realization that I'm going to be going for way too many artifacts/skins, it occurred to me that some of these feats for unlock may not have to be repeated. Hidden skin criteria will likely apply specifically to that artifact, that's almost a given. What will happen with the Prestige ranking in PVP? Will that be a character-wide unlock, meaning the skin for each artifact that character has will unlock? Lastly, what about the Glory of the Legion Hero unlock? I would sure hope that one is account-wide...

Any thoughts?