Hi, my interview was yesterday and I was approved without any problems for the immigrant visa but the consul said that the remainder of the time on my 2YHRR could not be waived. So I have about 6 months left and when it gets close to the time when I will be done with it I need to call and arrange for mailing of my passport so they can put the immigrant visa in and mail it back to me. The good thing is that I did not have to present any excessive documentation of my stay in my country, passport stamps were sufficient and that counting the times when I had gone home for just a few days also was accepted. In my case, I spent another 7 years in the US on different visas before coming back to complete the 2 years. So any vacation and home visit prior to that, which amounted to about 2 and half months, were counted. I presented a spreadsheet with all the dates coming and leaving home and counting the months and days I spent there. You have to prove 730 days in total (but can be with interruptions). The problem is that I went back to the US while completing the 2 years and the time spent there had to be added to the total time home.
Otherwise, the interview went really easy, we have a good case after all being married for 5 years, having a child, owning a house and filing taxes together for that time. I wasn't asked for any photos and not many personal questions besides what we both worked and what I intended do when I got back to the US.
I hope this post was helpful for people with previous J-1 visas. Good luck to everyone!