I would not over winter them in the house. I'm by no means an expert but I would think mums need a dormant period, perhaps even the cold of winter. But that is just my gut telling me that, not any scientific information.
I do not mulch anything. I'm a no fuss, no muss gardener. If it can't survive on its own with the exception of maybe some watering in overly dry times it just doesn't stay in my gardens.
