Oh, the glories of working for a not-for-profit.
Just talked with my boss and she told me that "oh its animated now?", despite having asked for animation. Agh! Thankfully without animation this becomes a lot simpler: namely, I don't need the Arduino anymore.
I already have the 12V battery. Our maintenance guy is going to charge it overnight for me. I did not think about using the cigarette lighter, and I am not sure how to safely utilize it without going out and buying something. Plus, I already have the battery.
I am about to go out hunting for 12V light strings, etc at Hobby Lobby, Walgreens, and where-ever else I have time for. Hopefully I will be able to make this work (electrically) and hand the actual decorating off to someone else.
Thought I do not need to use relays for the project as is, would my circuit above have worked? It is my understanding that the Arduino pin out activates a transistor that completes the circuit to the relay, I just did not draw that part of the diagram. (or even bother to use the correct symbols 
)