Concerning the wall:
Some people are saying that it would be best to built the wall out of bricks, becuase they are strong. However, the number of situations in which the physical strength of a brick wall would be needed is absurdly small. The physical strength of a wall is irrelevant, as long as it posesses at least some minor degree of strength. A dirt wall, possibly reinforced with timber, would certainly have the required strength. It would also be a lot easier and faster to build than a brick wall. Furthermore, such a dirt wall can easily be made thick enough to stand on, whereas a brick wall tall enough to be effective and thick enough to stand on will need an obscene number of bricks.
Concerning the structure of the shelter, the physical strength is also not important, as long as it is strong enough to withstand the weather. If any attackers manage to make it to the shelter, then we're definitely doing something wrong.
Concerning the traders, I suggest we side with the second ones. Not only will their service discount potentially be very lucrative, but we have plenty of access to exactly the stuff they need - food and land.
For the industry, I suggest that we focus heavily on food, especially fish. Not only are our own supplies dangerously low, but the traders are in big demand for food, which means we can get a really good price from them.
I would like to propose the following plan of action for the buildings in the settlement:
First, we build the wall. It will be made out of dirt, about three feet thick (so people can stand on it), and the edge that faces the moat will be plated with timber, so we have a strong vertical surface there.
Once we have a section of the wall up, we can start to build the shelter. We can make a mud structure, using the inside of the settlement wall as the rear wall of the shelter.
Now, a few points I'd like to make about the possible building materials:
Bricks are not good. In fact, bricks are very bad. Not only do we have the issue about the strength being not needed, bricks take obscenely long to produce. Our current brick stockpile is 182 bricks, after we spend pretty much a whole day with two chromes working solidly on them. If we take a chrome to be about six feet tall, we have roughly enough bricks to build a wall six feet tall and six feet long. In order to build a brick house big enough for just one or two, we would need hundreds, possibly thousands of bricks. In order to build a brick wall around the settlement, we would need tens of thousands of bricks. The time required to manufacture so many bricks, let alone assemble them into a wall, would be far, far too much.
Mud, on the other hand, is good. Mud buildings are plenty strong enough, can be build very fast, and have materials in abundance. Furthermore, the very act of harvesting additional material can do done in such a way that it expands out moat and makes our defences better.