An advice tree is always a way to engage your guests. They can leave you words of wisdom or wishes.
If you go with the pinwheel theme, you could use these adorable favor boxes for your guests, topped with a pinwheel!
Clear bulbs are a really inexpensive and beautiful way to decorate. Suspend with thick ribbon and fill with flowers, candy, ribbons, etc.
If you decide to do the mustache idea, you can get chocolate mustache molds and make lollipops. These are classic:
A black and white cupcake: White paper, white cake with an Oreo on the bottom! I can't wait to make these for a party!
Consider making some sort of "Thank You" sign for a a few pictures, then you can print them up for your thank you cards!
More charming black and white cakes!
This next idea is brilliant! First, you have your candy display table. Beautifully decorated.
Then, your guests find their "take home" box, displayed or set up however you wish and fill their boxes with candy for the ride home. LOVE this idea!
Have you thought about doing everything in black silhouettes? You can decorate your cake this way, frame silhouettes of a wedding cake, cupcake, rings, flowers, shoes, happy couple, temple, and etc.
Happy planning!