In my opinion, they are likely goners. Regardless of how cold....within limits anyway...I would expect the cluster to buzz after a sound thump. If they are alive the bees at the center of that cluster should still be warm.
Dead, head first into cells during cold weather. It sounds like starvation to me. Even with honey still in the nest, its location and proximity to the cluster are still essential considerations.
Even if they starved, it still may not a result of poor beekeeping. I think most 'good' beekeepers have had a colony starve, with remaining honey in the box. A bad combination of events can cause that cluster to end up in the wrong place....at the wrong time.
Let me never fall into the vulgar mistake of dreaming that I am persecuted whenever I am contradicted. - Emerson