You might try putting them into dormancy in your basement if you have one. (See my post about putting ensete to sleep for Winter.)

Can't comment on the other bananas but Musa basjoo should be perfectly hardy in zone 7. It's basically a giant perennial, will freeze to the ground and spring back next year. Cut off the leaves after they freeze and use them as mulch, but leave the stems standing until spring; when the weather warms up again cut them down to the point where you see living tissue. Some people wrap the stems to keep them from freezing and get a head start the following year, but I don't even do that--they grow so fast it's not really necessary.

It's pretty easy to overwinter basjoos and keep a lot of the stem alive. All you have to do is get something like a fence/55 gallon cut open barrels, or anything that can hold together a bunch of dry tree leaves or straw for insulation over the winter.

Here is a link that might be useful: musa basjoo overwintering

mine die back and get to about 12' in one summer. I usually try and dig up one or two pups to keep in the house as back ups in case we have a really bad winter. I have had EE's survive in the ground but usually also try and dig them up.

thank you for the info. so mksmth do you cut them back at all, or just leave them as they are to die back?