I think those are misnomers. There are basically three types of "shanks"; low, high and slant.
Here's an explanation of "shanks". The most common is low shank. The slant shank is a Singer Sewing Company invention and is only on "vintage" Singers. There is no "medium" shank that I am aware of. Some of the newer high-end machines have company brand specific feet (only their feet fit on their machines, like Bernina).
Since I don't do FMQ, I'm not exactly sure what the explanation would be as related to templates. The template is the plastic odd shaped "thingy" that you use as a guide for your foot as you move the fabric under the needle. There are many "mavens" of FMQ; Angela Waters and Leah Day are two of the most famous. They and many like them make templates for FMQ, plus have classes and videos for help in learning. Most feet used in FMQ are similar to "darning" feet.
As far as I know, the Westalee company (I believe they are an Australian company, but not sure.) is the first to come out with the feet and rulers for FMQ. As I understand it, Westalee only makes rulers and feet for low, high and slant shank machines. Sewsteady is their USA manufacturer and distributor.
FMQ takes a lot practice to master. There are all kinds of tips, tricks, classes and videos for learning FMQ. There are a plethora of videos on youtube.com. I would suggest you buy only one or two basic templates until you master them. Sewsteady seems to be a good place to start.
Just to let you know my history with FMQ; I bought a beginner Westalee ruler and foot for my (most used machine) vintage Singer with a slant shank and then figured out that my feet dogs wouldn't drop, which I just didn't think of at the time. I still have the foot and ruler, but have not bought another foot for one my other vintage Singers that do drop their feed dogs.
The ruler I received was a 1/8 in. thick ruler. My guess is that Bernina takes the 1/4 inch ruler.
bkay