Paul's Scarlet makes a really nice bonsai, and is very cold hardy. there are also native species of Hawthorn, native to Michigan that you could use. Check Oikos Tree Crops - near Grand Rapids - they have a lot of native trees.
http://oikostreecrops.com/
Also for you list, along with apples, flowering crab apples, and cherries, consider flowering quince. Chaenomeles hybrids. For winter hardiness, purchase them from a local landscape nursery. I have Scarlet Storm and Orange Storm. Both are very hardy, -15 F (-26 C) this last winter and did not loose anything, not even twig die back. These two are larger growing quinces, I picked up 5 gallon nursery pots, and then chopped them back to about 8 inches tall. They back bud like crazy. Flowers in early spring and a scattering of flowers off and on all through the growing season. Nice minor flush of flowers in autumn. A classic flowering quince often used for bonsai is 'Toyo Nishiki', it too is quite cold hardy. I would avoid Chojubai - for wintering outdoors in Michigan, Chojubai, Hime and some of the other dwarf flowering quinces popular for bonsai need a little winter protection. I kept my Chojubai between 28 and 38 F for the winter. My 'Contorted Red' flowering quince survived -15 F planted in the ground and covered with snow, it is a medium small quince - not dwarf, but smaller than the 'Scarlet Storm' and 'Toyo Nishiki'.
Another super winter hardy flowering shrub for bonsai is Potentilla. Nice yellow flowers over the summer.
I am also in my first year of trying a Service berry, Amelanchier x grandiflora, look for one of the varieties listed as being more tree like, some Amelanchier species send up multiples of suckers from root stolons. You have to keep after the suckers, prune them off, to keep them tree like. Nice white flowers, small leaves and small edible berries. Super hardy. Several species are native to Michigan.
There are many other species of flowering trees, but the ones above are all super hardy, and frequently used for bonsai with the exception of Service berry, the Amelanchier is not used that often, but so far seems a good candidate.
