Dont' take anyone too seriously about "magic numbers" of what is ok vs not ok for space for chickens. For one thing, it depends a lot on your purpose/goals/philosophy; for another thing it depends a lot on your particular hens' personalities.
5 sq ft indoors plus 5 sq ft outdoors (apiece) is pretty tight quarters, but you can likely make it work. Michigan winters will be a problem. Hopefully you will luck into very placid, getting-along-together hens. Your two main problems will be the risk of cannibalism getting started (chickens can be quite amazingly violent with each other when stressed or bored) and the difficulty of ensuring adequate ventilation in such a small coop. The latter will be made easier if the coop can be located right up against a building or fence such that there might be a very wind-protected location for the vent you leave open, and having that vent be at the opposite end of the coop from the roost. You may still find you can't always leave a vent open and thus have to put more energy into seriously CLEANING the coop every day. Deep litter would not be at all a good thing to try in such a small coop btw.
Concrete is actually a really
good base in some ways, because it is so predatorproof. You will of course need to cover it with something -- I would suggest a deep litter based on things like mulch, straw, nontoxic garden weedings, dead leaves. With the run being that small you can ensure it is pretty well protected from precipitation in wintertime -- cover 3 sides with plastic or suchlike, DO NOT wrap the whole thing your you will have big humdity->frostbite problems -- which will mean minimal "thaw stink" problems, and without soil udnerneath it you will not have to worry about mud. Then periodically you can remove all the stuff from the run, compost it a bit longer and use it on garden, replacing with fresh stuff. I'd suggest aiming for AT LEAST 4" of stuff on the concrete, and it can pile up much deeper as long as you aren't letting it get nasty.
If the comment about electric fence atop the privacy fence wasn't a joke (and since you also mention razor wire, I guess maybe it *was*
) do make sure to check your local bylaws, as in many urban/suburban places this is illegal and can land you in a lot of hot water.
Make sure your coop is very raccoon-proof!
Good luck, have fun,
Pat