Lancaster has said before that it's Watson vs. Ashton for the right wing berth, and May vs. Nowell for the left.
I'd go May/Watson. But I guess I'm biased. May has more experience than Nowell and Watson combined, can cover 13, is actually a winger, is in great form, is scoring lots of tries for a team near the bottom of the league and has earned the chance anyway.
Also, given that Yarde has so little experience at international level, I'd be tempted to leave him out if the new players did well. If he was like Tuilagi or Corbisiero, I could see why we'd bring him back. But Yarde should earn his place.
btw, I have the funny feeling that Ashton may actually be dropped this time. Because it is too obvious a call to get wrong at this point, and I don't think Lancaster is a fool.
I wish he'd have the guts to give Ford a run out though.