I would plant each in a pot of good potting soil, perhaps tent them with a bag, making sure you ventilate from time to time, and keep them indoors until you can harden them off in the spring. Cut the flowers off for convenience.

In this damp zone 8, I'd pot them up in something with good drainage, trim back the tops including the flowers, and put them outside someplace semi protected - porch, under an evergreen. If an especially cold storm should be in the forecast with temps into the teens, they could be moved temporarily into an unheated garage.

The roots will continue to develop where soil doesn't freeze, low indoor house humidity wouldn't be an issue....

Depends what zone really for a lot of plant life. Here in Pa. I would take and dig a hole and put the container down into it and back fill the hole myself. Then put a couple inches of mulch over the area. At the same time I would watch that no mulch touches the stem of the plant.