Can I use freeze dried fruit powder to add color and flavor?

I've made these successfully the way the recipe was made, but added a little food color. That said, as long as your "add in" wasn't going to moisten the dough more than what a few drops of food color would, you should be fine. I can't promise anything, since I've never done it, but I'd imagine that what you describe is more like a powdered food color, so I assume it would be just fine. They might not be as "shelf stable" because of the addition of the addition of a perishable powder, but I'd also assume that whatever the shelf life of the powder is, it would be the same, or similar, for the finished conversation hearts. Good luck!