Hang in there M her nastiness will pass. My K exchanges were pretty wierd in the beginning, I was nervous and lacking confidence. 7 months in they are much better these days and my W is much more friendly. She lost her nastiness about 2.5 months ago.
Continue dark contact only around money and kid stuff. I never look to initiate contact and I don't ask them what they did during their time spent with the W. I only know what they offer up.