Fuchsias can be overwintered growing, or, more easily imo, dormant. Rather than type it all out I suggest you do a little Googling. There are lots of sites that will tell you how to do it. Here's a start. Wherever it refers to a greenhouse you can just as well use a glazed porch, garage, basement, shed or window sill in a cold room. As long as you keep the temperature low to avoid growth. Overwintering Fuchsias

can it be a dark cool basement closet without windows?

Yes - but the plant must be completely dormant, completely dark and very cool. And keep checking. If the temperature rises it will try to grow and without light it will die.

what temp do you think it needs to be below to stay completely dormant?

Just above freezing.

I am thinking I will take cuttings too, just in case I loose the plants. I think it will be hard to find a place just above the freezing temperature.

mnwsgal, I am so happy to hear that! I will try it in my mom's dark basement closet which is cool but more like the temp you are describing. I don't have a cooler place than that. I have made cuttings too -just in case, but am not sure if they'll stay alive for 6 months!