Post History
Although I like the concept of character interviews, in this special case, I would sketch the entire character's biography. In that way you not only have a clear idea of the character's personality...
Answer
#3: Attribution notice added
Source: https://writers.stackexchange.com/a/21745 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/
#2: Initial revision
Although I like the concept of character interviews, in this special case, I would sketch the entire character's biography. In that way you not only have a clear idea of the character's personality state at the two times of your story, but you will also have a keen sense of the character's development in-between (think Boyhood here). It's more work, but for me, it pays off in the end. If you want to stick with the interviews, I would definitely do the extra work and write both interviews.