I think the whoopie pies are a great idea.
Make them a little oblong in shape and you could pass them off as either whoopie "eggs" or whoppie "carrots"
A little of the filling on the edge and place a little coconut tinted green.
I think it will make a great display for a dessert. Sprinkle a few jelly beans around them and you just might have a centerpiece for the table. The only problem would getting people to not eat them first. It is hard to not eat a whoppie pie!