I haven't tried any of them, but was going to get a hardy banana. I keep the plants that are not my zone in their pots. I bring them in the basement and put them under lights in the winter. It works with palms and Jasmine.
Sandy

Hardy banana..aka musa basjoo.

Dug up my basjoo last fall, threw it in the basement, and replanted it today. Bananas' root system is a corm, just like a glad. So if you have a cool place to store them, then it should work fine. Some people leave basjoo in the ground and mulch them, but in doing this, you will lose the pseudostem in Iowa.
When you say mimosa, if your talking about Albizzia julibrissin, try the hardier type: EH Wilson Mimosa.

Joe,
I live in Bettendorf and my musa basjoo were overwintered in the ground under about two feet of mulch. They started coming up about three weeks ago and are about three feet high already. I also overwintered a needle palm and two sabal minors successfully in the ground. They took temps down to about 5 degrees before I covered them with a plie of dry leaves for the coldest periods. I also have two Southern Magnolias that eventually became defoilated but are now starting to put on new leaves. They had no protection and should be even more cold hardy this year because they will be more established.