In scenario 1, Person A works for Wal-Mart and Person B works elsewhere.
In scenario 2, Person A has no job, and Person B works at Walmart, and Person's B previous position is unfilled.
I will also grant that as wages rise, certain jobs simply cease to exist, because it becomes uneconomical to pay anyone to do them. Being from Denmark where wages are very high, I was astounded to be greeted by not fewer than ten clerks in a small, mostly empty Swatch store I visited in Beijing. To have that much staff to do mostly nothing can only happen where wages are extremely low. If wages were to rise, one by one those clerks would probably be laid off. But not because a more skilled person would claim their position, but simply because it would become too expensive to pay any person to do that job given the value it creates.
However, there are some additional factors that complicate this picture. If there are fewer unskilled jobs, people will adjust by working to become more skilled. If people have higher paying jobs they will spend more, producing more jobs. If there are many unskilled people looking for work, there is incentive for somebody to find a way to make use of that resource.
But really, the only point I sought to make here was that your original comment which didn't look at the non-skilled worker was missing a bit part of the equation, and so its logic didn't work.
Citation wanted. It really doesn't make sense. Sure, a different class of applicants may fill those higher paying positions, but either those people weren't employed to begin with, which contradicts your point, or they had to leave other jobs to apply for this one, creating open positions where they left, which results in overall employment staying the same.