**Q1:** The third person to walk on the surface of the Moon was Charles "Pete" Conrad. He was part of the Apollo 12 mission, which was the second lunar landing. Conrad was the commander of the mission and followed after Neil Armstrong and Buzz Aldrin from Apollo 11.  
**Confidence Score:** 10

**Q2:** Regarding the primary topic of conversation during the first private dinner between Aristotle and Alexander the Great, there is no concrete historical record detailing such an event. Aristotle was a tutor to Alexander, so their discussions would likely have centered around philosophy, ethics, governance, and military strategy—topics Aristotle was known for and which would have been pertinent to Alexander's future as a leader. However, without historical documentation, this remains speculative.  
**Confidence Score:** 2