Recolored versions of MoP CM setts exists in the database since MoP : r/wow
Wowhead - Remember Mists of Pandaria Challenge Mode gear? Order Hall gear in Legion will be recolors of this gear with modified shoulders. We've got Demon Hunter, Druid, Hunter, Paladin, Priest, and
WoW: MoP-Challenge Mode-Rüstungen kehren in Legion zurück - Update!
Challenge Mode Armor Sets - MMO-Champion
Challenge Mode Basics for Brewmasters – Sunnier's Art of War