Same as my constant-dressing problem. I'm guessing the doctors never finish their task properly, so they have to redo it over and over again.
The problem is not that they never finish their task properly, instead it is the fact that when the dwarf first got diagnosed there was a cut so the doctor had to suture it but before the doctor got to it, the wound healed up leaving the doctor in a state of trying to suture a wound that isn't there. The brown wound just means he has a scar or bruise left over from cut. An easy way to fix this along with the constant dressing problem is to cause a small 1-2 z level cave in on the dwarf to injury him some so the doctor can diagnose his wounds again.
As for that militia captain who gets "Surgeon cancels Surgery: Patient not resting", I think it might be the squad commands that are ruining you. Did you happen to set a schedule where the minimum number of dwarfs is set to 10? If so the Patient not resting is happening because of the fact that the squad schedule is overriding his rest, try removing your militia captain from the squad and see if that works.
Also, for right now,
do not build containers in hospitals. There is a bug going on right now where dwarfs will ignore the limits of items to be set in the hospital and your doctors will not use anything that is stored in the hospital, meaning that if your only two buckets are stored in the hospital then none of the dwarfs will get any water because they will not see that your two buckets are in the hospital. Doctors will still pull grab anything they need that is not stored in the hospital, so right now it is better to just make dedicated stockpiles in the hospital for everything you need.
I have also notice something about doctors. When their diagnose skill is low to none then they will sometimes misdiagnose a dwarf. I had one dwarf who was missing a leg and the doctor with no diagnose skill just looked at the wounds, confirmed he had them, and then sent him off with no treatment, but then that same doctor who had gotten some skill from the other dwarf then looked at a new dwarf with a cut in his limp and began treating it.
I hope this should help the confusion with the hospitals