Powdered buttermilk is found in my area in the baking aisle. It is often found near the regular powdered milk too.

Bisquick does use shortening, in fact when it was invented it replaced the traditional biscuit fat, lard, with shortening to make it not need refrigeration. Remember shortening is just a solid form of vegetable oil; it has been hydrogenated thus the comment that comes next...

Here is one way to make it controversial, shortening (and thus bisquik) are trans fats. http://www.webmd.com/content/article/72/81813.htm