They asked standard questions including background, work experience and the reason why I wanted to leave my previous job... etc.
Hiring a new person for them is like choosing a new member to join their family. Always be sincere and honest because they are most likely to find out within 3 month probationary period. The company is small, less than 15, so you will work with them frequently.
Be prepared to answer questions from the principals for the things that you say during the interview and it is always good to bring supporting materials with you. The principals only interview with people who have portfolio. They are very "visual" people.