I'm using a different recipe than NFSC, how long are sugar cookies, baked and decorated good for?
I think that unless they are frozen, they really are only 'fresh' tasting for about a week. If they are tightly packaged, a bit longer. The butter gets to tasting a bit funky after a while.
can you freeze fully decorated cookies?
There are numerous threads about freezing decorated cookies, but yes you can. If you are using a lots of bright colors, there is a risk of color bleeding if there is condensation.
You can limit this by keeping them in a sealed container, and thawing in the refrigerator. Unopened, any condensation will form outside the package.
I freeze decorated cookies all the time and never have a problem. The colors of the ones I freeze are NOT bright. So, not sure about the bleeding issue.