Investors & landlords

1) I think the two terms are NOL vs. passive losses but am not sure about the terms. Which one should I use? My accountant is pushing for passive losses. The facts are that I did not file 2014-2016 yet, I had about $20,000 in rental losses per year, I managed the rental actively myself.

2) Is it too late to file for carryback to 2013 if I am still with in the 3 year deadline to file 2014 taxes by April 2018?