John C Daley

They are shown being driven by a jackhammer, which may work for very hard conditions.
I ask, is there ground that does not heave with the frost?
We dont have that problem in Australia, so I find the whole issue fascinating.

Very interesting;
Diamond piers

I am one who likes to make stuff.
If you search diy evaporative coolers you will find many examples of small ideas.
I chose to buy a secondhand unit and fit that, because it was so easy.
BUT, I have seen wind towers in the middle East and India where air is drawn out of the house via the tower and replacement air into the house is drawn from a cool courtyard with ponds.

cooling towers are similar but work backwards by being the source of the air into the house.
Membranes are installed high in the tower, water is applied to them and air is drawn through the membrane, down the tower and inside the house.
The is drawn down by ventilation systems which can draw air through the house.

What did you finish ending up with?

Have you considered logs with an external covering to improve its life?

In Australia its possible to buy a mozi filter that fits in the plastic pipe.
If you are using mesh, I would insert it inside the T branch that heads to the tank.
So poop will head down the trap and water will pass sideways through the branch, good luck.

Wind towers have been used in the Middle East for a very long time. Look them up.

The flat metal stip lays flat and is quick to be installed.
We even can use a small device to tighten the strap, its 'U' shaped with a bolt and the 2 'U' shaped parts are pulled together by the bolt, very clever.

A couple of technical matters.
The floors are made of concrete, not cement. Cement is an additive to concrete.
If its cold on the ground, insulating the slab may be worthwhile.
Do you have far to travel to the site?
I ask, because if so, it may pay to work quickly on roughing things out so its not bad to stay there on the weekends.
If you dug the post holes, set up roof posts in steel and concrete them so they are stable, you can put up the tin roof and wrap something around the poles to break the wind.
Then when you have more cash, concrete the slab etc.
Then you have basic shelter and somewhere to store things like windows, doors sinks  bath etc if need be.
Think about having a hot water storage tank of any sort in the roof structure finally.

It does not look that deep!
Can you fabricate the stirrups yourself?Some hoop iron diagonally across the roof frame both ways should be a great help in creating lateral stability of the new posts.