Question
I bought some Kordana mini roses and I'd like to know if I can plant them outside in the spring. I live in northern Michigan, will these roses make it through the winters and come back each spring? If not, how can I keep them growing in the house?  

Answer
I cannot help it - I have to quote the Kordes Rosengarten website description of its Kordana introductions:  

"Kordana?potroses are special miniature roses, which are developed for the utilisation in living spaces, but they are very suitable for the garden, like terrace, balcony and for terracotta planting. Furthermore Kordanas becomes more and more favourited as fashioned elements in floristry works.  The growing popularity of Kordana potroses is based on special quality characteristics, like big flowers, similar to hybrid teas, an extreme long shelf-life
and the darkgreen, healthy foliage." (http://www.kordes-rosen.com/englisch/).

What I can tell you is that these fragrance-free Kordes hybrids are true miniature Roses that will never reach higher than 8 inches tall in the pot.  They are most famous for the long shelf life of their flowers ("an extreme long shelf-life") in or out of the pot.

Here is (a cleaned-up version of) the Kordes official statement on "How to Care for your Kordana Roses":

"Kordana pot roses do not need a lot of care or attention.  If you do it right, you will enjoy your roses for a long time.

Location:  Kordana potroses do not do well in temperatures that are too high for them, so avoid placing them in direct sunlight during the summer months. Placing the roses in cool spot with plenty of light will help the flowers last longer and buds will be able to develop for full flowering.

Water:   Kordana?potroses do not do well if they dry out. Be sure to water your potrose from base every day in the summer and every 2- 3 days in the winter.

Fertilizer:  Add fertilizer to the water once a week in summer and once all 15 days in winter, clip off dry foliage and withered flowers.

Again like new!

After the rose has finished flowering, cut the plant back up to 5 cm (2 inches) above the soil. It will reflower within 6 weeks under the right conditions. A bigger pot and new soil will help for healthy growing."

Growing any Roses indoors is always going to be a challenge for anyone.  These are perennials that need a cold period and dormancy to do well, even if that cold is somewhere in northern Florida.  Indoors, be prepared to battle spider mites first, with humidity a challenge even in a cool parlor with a sunny window.  If you can keep them alive through the winter, you can get them outside in the spring, where they'll recover and thrive through the rest of the year.

As far as planting any Miniature Roses in the garden, Miniatures are not reliable in areas colder than Zone 6.  My ignorance of the world can only guess that your Northern Michigan climate is way colder than Zone 6.  Global warming may get it there 20 or 30 years from now, but in the meantime, I do not recommend that you plant any Miniature Roses outside, even with protection.