Other then I know the commander in each camp can not be killed, you can take them on without a bounty. and there shouldn't be any more patrols with prisoners.
You completed it? you took over Solitude?
Very disappointed I was when I found out I could not kill the commanders. As an Imperial I never attacked the Stormcloak camps after the war was won, since I was actually sympathetic to their cause. As a Stormcloak I wanted them all out so went after the camps, it was one way to discover an interesting way to get your fighting skills up. I change to getting my heavy armour skills up I will go after the remaining camps.
As to the OP question, there are no Imperial soldiers roaming around my cities except for a few named NPC's, and no escorted prisoners that I have seen so far after the war was won for the Stormcloaks. When the Empire wins my cities are littered with malcontent's still fighting the imperials, especially in Riften. I never got a bounty for killing the enemy, no matter which side I was on. But I do not interfere with the local soldiers and guards in the cities when they attack the enemy. I leave them to it.