Remember, you are only being repetitive to yourself. Do not leave out important information because you have already discussed it with another individual. A new hire will frequently join you for lunch. This is the time to ask questions about the environment within the company and in that city. Whatever is discussed, always remain professional.
Most people recommend refraining from alcoholic beverages during any meal.
At the end of the day, a company representative will usually summarize the responsibilities of the job and address any unanswered questions that you have. If not mentioned by the representative, you can then ask when you may expect to hear from them. Let the representative bring up salary. Follow-up is very important. A thank-you letter restating your interest is essential.