You will need to use some kind of wood screw and not use the wing nut and bolt. Also, MDF is not a reliable source to anchor to. When installing your sink, make sure you also use some kind of adhesive or sealant between the sink and the counter top. This will help anchor the sink to the counter top in addition to the clips that you have.
this particular product is not available at any Home Depot store front. However, if you go into your local Home Depot, you can order, and have them to your home in a few days
No, it does not come with the brass anchor. However, each under-mount sink clip includes the screw, clip, insert, washer and washout needed to secure the mounting clip in place.
Include in the package
please check before you buy sink
I haven' used the ones from Home Depot but they're all usually the same. You drill a hole in the granite and install an insert #like a screw anchor# The post will screw into the insert and you place the clip on the post using the wing nut to tighten it against the lip of the undermount sink. These are used in addition to a bead of adhesive/silicone between the sink and counter. Many installers will just use silicone without the clips but we've seen more than a few sinks where it started to separate from the counter and have had to repair it using the clips. Always better safe than sorry - install them during sink installation.