You kind of forgot the two easiest way:
Sneak into the fort, go to the first floor, there you can chose: Sneak past the court for the escape mentioned in 5 or sneak to the bridge open it and leave the fort using the bridge mentioned at 4. To have a way back the second on is the better one, and will also lead to the trader behind the bridge. But you will have to beware of the patroling magister, to not see you will you try to open it.
Also your Nr 1 is totally wrong: You don't need Withermore for the boat, you just need to save the kid Han from those two magister, who want to knidnap him.
I'm pretty sure, Harbour is not doable without any fighting, you will need to get past all the guys with Paladin Cork first anyhow.
You can leave the underground without any fighting, if you just sneak close and grab the key lying on the stool. In you options is also missing the 2 other ways to enter the underground: getting told the about entrance to the fire snail dungeon and following Gawain using teleport. Perphaps there is even a third way: getting thrown in jail, but I guess that works only for one char (at least if you got his collar removed).
If I'm not wrong, you missed a chest in the fight against the hound master, just as an add. ^^
