But if they write it that Lightforged Draenei were resurrected into DK in some event after BFA, they could make the lore whatever they want. Who knows, maybe Blizzard is planning unique animations that are light-based similar to unique druid forms and shaman totems.
Also, I really think Lightforged Forsaken are going to be Horde’s next AR and be models based on the asian model (can’t remember if it’s Japan or China, to be honest) that I see people rave about with Caelia as their leader. I’ve seen players ask for Undead that aren’t rotting for years. I’m not one of them. I like having half of my face ripped off, but I’ve seen threads requesting “pretty” undead. I’m guessing a bit of a fan service for Sylvanas and Nathanos supporters.