score:5
The amount of taxes and duties varies greatly based on:
You can find the rates for duties in chapter 22 of the US Harmonized Tariff Schedule.
It can range from free to 23.5 cents per liter. As you can see in chapter 22, it depends a lot on the exact type of alcohol, both for taxation and reporting purposes (there are dozens of different codes).
So it's going to be important for them to be able to read the label. You might be able to pull it off by taking pictures of the bottles before decorating them, but probably only if the bottles have shapes that are specific enough they can be recognised from the pictures. It's probably better if the relevant parts of the label (type of alcohol, strength, country of production...) remain visible.
I'm not sure if CBP officers would also apply local sales taxes when importing in a state that has them?
Of course, there are plenty of other federal, state and local regulations regarding transport of alcohol in the US.