So have you come up with a good story to tell just how you killed each one of those before you had them mounted?
After hanging, if you don't want it moving around use Museum Putty. It is not permanent, and won't harm wall finish.
I took Don's idea and played with the Museum Putty here and there too. After deciding I didn't what to hang the art after all, I just made faces out of the putty and said the heck with it.