Yes, vegan peppermint bark is great to freeze!  As a matter of fact, I think the freezer is the best place to store it. You can even eat it straight out of the freezer.  Just be sure to package it in an airtight container so it doesn’t pick up the flavor of the freezer.  If you don’t keep it in the freezer, I recommend keeping it in the refrigerator or in a cool dark place so it doesn’t melt.