Gumphri,
I need to get some more details from the architect as far as the heating/cooling details of the house. I'm assuming that the wood fiber sips you mentioned are Stramit panels, made from wheat straw. I make my own insulated panels for my houses, so I could conceivably use Stramit panels and laminate them to ply or osb.
I've been interested in Stramit panels for a while. I would love to use them in a project.
It looks like the weatherstripping that Jon Senior mentioned is basically poly ester foam. I think that if done right that foam would do let any possibly trapped moisture move out. I suppose that in my climate any problem moisture would originate from inside the house.