1. Are you guys expecting another baby?
    No woman will ever believe that you asked because of her "pregnant glow".
  2. How did you break your foot?
    ...or any other "Look, there's an injured person! I bet no one has asked them what happened yet" assumption that leads to similar questioning
  3. Are you dating anyone?
    If they were that excited, you would know.
  4. Do you want to play corn hole with us?
  5. Are the two of you dating?
    Ask separately. Ask their friends when neither of them are listening.. Ask anyone else.
  6. How is school going?
    Nothing says "I have no idea what to talk to you about" like asking a student about school.