I used long strips of packaging tape to cover each object. Before putting the tape directly on the frame I removed a good amount of the adhesion by applying/removing from a different surface. Once the frame was covered, I marked the corner of each object with a dot (luckily there were no curved features). I originally tried to draw the complete outline of each object but that was not working well. I then removed the tape from the frame and laid it on a thick card stock. I then connected the dots and cut out the card stock giving me the stencil. I made sure to slightly oversize the stencil to ensure each feature would be completely covered.

Edit: there were a few curved lines in the letters. I just used a series of dots to create the arch.