I guess it depends on the art style of your game. You could create cut out animations where different body parts are separate objects that move on their own via bone-driven animation or via the AnimationPlayer node. You could then create targets for your props to follow. If you use spritesheets though, it will be difficult to use this method, if not impossible. In that case you would have to create a basic character template in the image manipulation program of your choice and then add all the different props on this basic template so as to create all the possible variations. This is a tedious process. If you have settled with spritesheets, I don't think there is much else you can do.