My dogs are like your cats. If I leave anything in paws reach they will eat it. I have a huge walk in pantry and that is where I place my cakes. Door Closed. My cakes are for family and friends only, so don't run a business out of my home.
Don't use real money. They have germs and are very gross. Don't want to make people sick either.Maybe you could make fondant "money". rolled up or hanging from the tree.
Wilton has a how to make cups and saucers out of cookies and cupcakes. Have to search for garden tea party I believe. I did this and everyone loved them.