I leave mine outside on the east side of a building and toss straw over them deeply. Next spring when it begins warming up and I see signs of life in the gardens, I uncover them water and leave them until they begin to grow...then in the ground with them.

I am not sure about inside with zero moisture. I would keep them in the sun and keep watering before tossing them. If you take it out of the pot you should be able to tell is the root is dead or has signs of life.

All my coneflowers are already up and the Tennessee variety is about to open the first bloom. So I would think if you aren't seeing anything yet, they didn't survive.

I keep things in dappled sun at the end of the driveway or up against the garage door. Protecting them from wind is important, but you gotta make sure they don't stay too wet.

I have pots of phlox and coneflowers and other perennials sitting out in my garden where they remain year round. I root roses in pots and leave them in the garden in those pots a good year before setting them out- until they have a good root ball. They are protected in with the in-ground plants. But I have put several pots of plants on the south side of the house to overwinter and they did fine. Mulch with grass clippings, hay or wood chips to keep their roots moist, but not soggy.
I water year round if need be. Winter watering protects the roots of plants and young trees or bushes from dry freezes.

My two cents worth.
~Annie