Applaud and Smite are for the Karma system built into SMF, nothing directly related to SMF Shop.
It's sort of like a reputation system. If someone does something good, you can applaud (+ rep) them, and if they do somthing bad you can smite (-rep) them.
You can also change the 'applaud' and 'smite' labels from your admin panel. So they will say, for example, '+ rep' or '- rep'.
About the shop buttons, you will need to edit the template file of you theme, Daniel will be able to help you better with that than me.