I hope you have tried Guo Tie Foxy? I think the oil used in frying changes the nature of that pastry.

I haven't, but I like xiao mai. In Hohhot, the filling includes minced/chopped mutton, whereas in Shijiazhuang I only came across beef xiao mai. The pastry is much thinner and finer than that used to make jiaozi/baozi here.

xiao mai is wheat, is it not, for making flour? Anyway, the Chinese are well capable of making refined pastry, using butter and all the business-but as you indicate a lot of the Chinese dough is just flour and water.