I did the same as you (diaper change, then feed) until my little one stopped pooping so often. If I did feed her first, then I felt bad waking her to change the diaper, but also really don't like her sitting in poo. We are cloth diapering and were just using prefolds with covers at first so even if it was just pee going all night without a change would leak through so I liked to change her at least once. Are you using cloth? This might make a difference in how often you want to change the diaper, depending on what kind you have. Once we discovered pocket diapers and more absorbent materials, and since that she only poos every few days right now, I no longer change her at night.