i have found that hostas are pretty forgiving. I think you can kill them with love before the cold will kill them.

I have an August Moon that has been in a 24 inch plastic pot for several years; it does better than the ones in the ground. I have had a June in a smaller foam pot for a couple of winters. I did not mulch either. I think I read the risk is too much water standing in the pot. Mine were out in the weather so they got rain. If you put them in a garage or out building you would have to remember to water.

I have overwintered them just by putting the pots close to my garden shed where they would be protected, and covering them with a good thick mulch of leaves. They've all come thru fine.

I overwinter about 100 hosta in pots. I wait until the pot is frozen solid, then lay it on it's side on the north side of a building. Forget about them until April 1. I stack them several high. You can put some rat poison behind them if needed to control voles.