Stillwood, I think your minis would fair better outdoors during winter than indoors- it's tough to provide enough bright light to keep roses happy indoors and they tend to get spindly and weak. If you want them to remain in containers you may want to consider overwintering them in the pots outside with some protection, like sitting on the ground next to a structure with mulch piled on them. I suspect they would be fine without protection in your zone, but an extended stint of 20F may damage the roots. Not sure about that, but better safe than sorry.
