Thank you for elaborated post with your experience @bernilli!
I'm surprised you did not take your spouse with you for 3 year rule, I even mentioned it in my post earlier as one of the reasons for applying under general provision when eligible for both. In my opinion, you were really lucky to have a cooperating and understanding officer. Not all of them are like this. You could have easily come across somebody who would be focusing all the interview on marriage just because the spouse wasn't there.
For anybody in this thread, if you have N-400 under 3 year rule, make sure to bring your spouse. More often that not, officers do expect them to accompany you. Not all of them will be satisfied with answer that it wasn't mentioned in letter. The application is based on marriage after all.
Good luck and keep us posted! Very lucky with short time to oath.
Please remember to update citizenship status with SSA and get a large passport book (it is a free upgrade)