1) Absolutely nowhere in either episode does it say it happens/ed to the 10th Doctor.
It is made pretty clear that River Song recognises Ten as the Doctor she knows. She's surprised to find he doesn't know her and later only notices that his eyes look older in her time. So, it's quite obvious that she met Ten. He hasn't aged in too obvious a manner when she first meets him, though, so this story can still happen even if we do see a regeneration in the last special, provided the Doctor doesn't make any contrary statements about his own time line in them. However, I'm not too keen on actually seeing this story.