You said this is for kids, right? Most likely they will not like to eat the dark chocolate. Also, does the school have a peanut butter restriction?
You might just use yellow. You could add a few pieces of brown to darken it a bit. Add one at a time and mix well.
Brushing the dust on dry verses mixing it with the vodka will give you two different effects. I seem to remember now that I had trouble getting the dust onto a chocolate item and I decided to just give up (it was turning out very streaky.) It works great with fondant though. You could do fondant; kids love eating that stuff, especially if you add some flavoring.
Or, to make your life even easier, get some of the gold foil wrapped chocolate coins. Print out some interesting pictures that have something to do with Chinese New Year, punch or cut out circles and use double sided tape to attach the pics to the coins. You can use regular computer weight paper, no need to use anything heavier.
You can also make your chocolate coins and get some of the gold foil to wrap them yourself. I think Wilton has little squares you can buy.