I placed the boards by the brackets I made to see how they will fit. Modified the brackets so they are both the same style now. As you can see below, I think it is going to work pretty well.
I also spent some time making a simple map of how I will trigger the sounds. I plan to use the Mini Commander HC1 and HC2 outputs to act like push buttons to control 2 different sounds. I plan to use LC1 input on the mini commander to trigger 2 more sounds. The LC1 will go to 2 different switches (likely reed switches) that will be meant to trigger the sound when each character is in their up position. Lastly, I could use LC2 for the final sound on the MP3 board. I'm pretty excited to be able to effectively use all the sound options.
As for sounds, I've used a MacBook, Apple TV, and QuickTime to record several bits of audio from the movie. I've edited these into various clips in Audacity and have more than 5 to choose from.