I don't think Griffin will be a DRK - I think he's just going to be a guy who happens to use a two handed sword...with a few neat tricks of his own. Much like Regula. I can't recall but did Ilberd fight with a two handed sword? That might be another clue that it is him if it is him.

Going back to the 'smoke rising' at Baelsar's Wall perhaps that has to do with the Amaal'ja - some sort of pact between them and the Ala Mhigan Resistance was hinted at and I could see it being a plot point referenced again moving forward.