As long as the pots aren't overly wet when they freeze, they should be fine. Shallow rooted plants like blueberries are used to their entire root system freezing anyway. If they're hardy in the ground, then with proper care, they'll be hardy in pots as well.
The biggest problem I've seen with these is that the bottom of the pot will be the last thing to thaw, and this leads to moisture buildup in the pot. Say the pot is frozen, and you get 8" of snow. The next day, the sun comes out and the snow melts, and drains into the top of the potting mix, which has thawed, and fills the side of the container that the sun is shining on. That night, it refreezes. If this repeats all winter, the results won't be good. I always put a waterproof light-colored covering over the top of soil before winter, to keep that from happening. There won't be much evaporation in winter, so it's better to err on the side of too dry than too wet.
Another thing to keep in mind is that dark pots, such as black or dark green (very common) heat up a lot in sunlight, so that in winter, the roots at the edges of the pots may warm up to over 70°F., while the core of the pot is still frozen solid. Not good for the plant at all. So I often insulate the outsides of the pots, and cover that with something light in color, like canvas.
On bringing the pots inside, that is usually a bad idea. Most cold hardy plants use winter as a dormant rest period. Having it be room temperature, or even 50°, will be confusing to the plant. It may try to put out growth too early, and harm itself that way, not having fully recuperated from the previous season's growth. It's also possible, if you are dealing with fruiting plants, that they require the cold period to form flower buds. When a flowering plant is labeled 'zones 4-8', chances are they will survive in higher zones, but won't flower and fruit properly, or may not go completely dormant, and lose vigor that way.
So I recommend protecting them outside, and not trying to overwinter them indoors.