There are 3 levers along that wall in the bunker, two over by the desk, and another beside a chest.
Had you let the 2 black ring members upstairs in the bunker surrender, you could have traded with them. They are not great merchants, but I did buy a couple things off them, and sold excess loot there until I depleted their gold.
The anti-dragon shields around the harbour and High Hall can not be removed, so you have to go there by foot (you can fly over part of the harbour shields and transform to drop down).
The fjords is the last major area before the Hall of Echoes, though in addition to caves, etc, there are flying fortresses and you can return to Broken Valley (which is now essentially another flying fortress). After the Hall of Echoes (in DKS or FoV) you will return to Aleroth, which will be opened up.
You will not get to fight Damian until Divinity 3.
