I have a couple of houses that I rent and I keep the temp at 55. I get long periods of cold I think colder than what you would get. I do have a very good insulated windows and it is a brick. I keep almost the same plants you have listed except african violets. I cannot seem to keep them alive even being good to them. I stage my houses and live plants give a lived in look and they rent and sale better.
I only water them maybe once all winter because it is cool.
