Since the teaser indicates that The Last Jedi will be following a rough The Empire Strikes Back blueprint, with Rey off doing Jedi training and the Resistance base blowing up, I can safely get excited for Finn and Poe’s romantic adventuring subplot, right?
For Keith not looking purple, I've seen other people theorize and think myself that it's because of magic. That either a magic user (druid or otherwise) put a spell on him- maybe to help hide him on earth?- or that he is actually a druid! To me the 'burn' on his hand looks just like purple skin, like it was a break in the layer of the magical illusion. And we know that in season 3 Keith is going to be discovering new powers! It may be a reach, but it would be so fucking cool eeeeeeeeeeeee.