Just wanted to pop in and say that we had absolutely no issues with customs or anything when we arrived in Cuba. Like I mentioned above we did take a spreadsheet, some receipts, and emails between my wedding coordinator and I, but they did not ask to see it, at all! The most stressful part was that my husbands(weird to say that still, lol) luggage was 'lost' for a while. Thank god for the guys helping at the luggage pick up. I was about to have a melt down because half of our OOT bag items were in the luggage. Besides that, everything went more than smoothly!
Good luck and let me know if you have any more questions.