Halloween // Help with a decoration creation!

Hey all! I’d like to create a mini grave yard diorama for some action figures of the universal monsters I have! I was planing on using some type of modeling clay to then bake it and make it solid but I don’t know which type to use. My biggest concern is that I want to mold their feet into it so they can always stand and not fall over, but I’m not sure what if any type of clay wouldn’t contract the size of the holes once baked! If you can give any advice or suggestions I’d appreciate it!