I think our extra evidence is what convinced them. I'm not sure why my husband was selected for an interview, our notes didn't have anything negative or of concern in them. I knew he was getting an interview almost 6 months before the actual date, so I began to collect everything and save every little thing! Our extra evidence that we took to the interview was quite thick!
I say bring anything and everything that you think could be beneficial! We used little post it notes on everything to explain what it was. Also, google possible interview questions and start going over them, and go over the applcation together.
My husband said that with each question, he tried to give them a detailed answer and tried to talk a lot lol, an example is they asked him where we met.. so he gave them specifics.. date, time, place.. who I was with, who he was with.. what I was doing there.
Are you planning to attend? I went with my husband because I wanted to be there for support. They didn't say anything to me except when we were leaving and she said congrats to us both.