Focusing on the DLC question, I believe that they don't have any concrete plans for it yet, but I'd be shocked if there wasn't at least some degree of internal consideration. Even just as simple as "hmm, this could work as DLC eventually." I imagine that a bunch of people have informal ideas in their head that will be brought up in a couple of years when they're in a position to consider that sort of thing. And I would imagine that including new classess and subclasses from outside the PHB would make for good early DLC.
