Nobody can say for sure why she is making small talk. She could be doing it out of guilt, she could be trying to keep the lines of communication open while the two of you work on selling the house, she could be testing the waters or maybe she thinks this is the first step towards a friendship. Who knows!
In my experience it is very telling when the WAS is "nice and pleasant" only when an exchange regarding administrative tasks comes up but really has no time or interest other than wrapping up the legalities (house, finances) of a M.
And due to the three sets of flowers and the gym issue you do have some ground to make up. And yes, you do want your W to feel you are slipping away and moving forward. If you stick with your C'ing, detachment and GAL endeavors eventually you will be just fine.
IOW, when the WAS starts to send messages about things that really are not necessary they are either fishing, tossing you crumbs so you don't become totally removed and they lose all control or maybe they think it is the "right thing to do". WHO KNOWS! Since we won't know don't waste time trying to figure it out.
As I said, I would try and remain NC for as long as you can (unless it is about the house or some other urgent matter) and if she establishes some sort of pattern of contacting you with small talk aside from business matters then maybe in a few weeks you can respond.
