I don't know if it would be appropriate to interview/question him...but I would choose Jesus Christ. I am a Christian and I think to be able to just be in his presense would be so amazing and magnificent I wouldn't have time to ask anything!!! But if I could go back in time and spend the day with him that would be awesome. Spiritually I am always in his presence and eventually I will be able to spend eternal life with him...but hopefully that will be a ways down the road
If I could interview a regular person it would be any of my ancestors just to know my history and where I come from.