Yuka is on the left side, she is three spaces wide and two spaces tall away from the ideal bridge location. Cheri is on the right side, she is four spaces wide and two spaces tall away from the ideal bridge location.
You would have to move both of them out to build a bridge there. For vertical bridges, there either needs to be at least 3 open spaces vertically between the bridge and the house or there needs to be at least four spaces horizontally between the bridge and the house, and it sounds like neither of your houses are far enough away.