Kakashi wins mid to high difficulty, of course assuming KA is restricted.
There are two possible scenarios:
1. Danzo has no knowledge on Kamui - in this case he gets warped before he activates Izanagi, so it's gg.
2. Danzo does have knowledge on Kamui - in this case he'll know better to keep Izanagi activated continuously, without breaks, against Kakashi, or else he risks getting warped. In other words, all Kakashi has to do is survive 10 minutes against Danzo, once he accomplishes that, he wins. Given his high stamina, this wouldn't be much of a problem. Doton walls and going underground is an efficient way of stalling. What's more, Danzo has little chances of knocking Kakashi out with fuuton, for example, out of a cliff or something, because Kakashi can teleport if situation gets dangerous. Add to all of this Kakashi's specialty, that is bunshin feints, and I see no way Danzo can defeat him during this 10 minute period.
So, yeah, mid to high difficulty at most.