Let's start with these common pieces =)
The pieces above are common hinged plates with frictions. (let's call them 1-finger hinge and 2-finger hinge respectively).
In my current project, I am not using them as hinges however...
Below is the leg that will be connected to the feet, via another different kind of hinges (non-frictional ones). If you look closer, the frictioned hinge mentioned earlier is built into the leg too.
Closer inspection showed the connected leg-feet with the frictioned hinge left as-is,almost redundant. You should be asking by now: Why isn't the hinge connected to anything at all?
Actually, I am implementing the 1-finger hinge to help prop up the feet when it's upright later on. You might ask again, why not use a generic 1x3 plates instead? Nope, it's not possible here... the hinge I used here , is exactly the length required... which is about 1mm short off 3 studs length. There is no other official LEGO parts which can fit the bill here.
By the way, due to the protuding stud where the edge of the 1-finger hinge meet (and they barely touches each other), it is not possible to use the 2-finger hinge to replace 1-finger hinge either.
Now let's look at the 2-finger hinge I connected under the feet (below). Since this MOC will have a bit of a back kibble on his body, the 2-finger hinge can be folded out to form a longer heel , and expand the footprint, thus stabilizing the MOC further.
And oh yes... why opt for a 2-finger hinge?
Reason 1: Anything exactly 3 studs will lock the part into place, causing zero clearance/unable to be folded out as heels. Anything 2 studs or less in length will make a lame-looking heel,
Reason 2: It's easy for me to pry out the tip of the hinge with my fingernails compared to other plates/lego parts =)
I shall end this post with a sneakpeek of the bottom half of my current project :)