If your buildings will be outdoors, then consider “Super-gluing” your joints. After you get the structure built using whatever glue you prefer to use, get some silicone caulking and apply it liberally to the inside joints. Make sure that it is seated well on the plastic by using your finger, hopefully in a rubber glove. Also you might consider reinforcing the entire structure with some interior cross members. A good hardwood like Ipe or other mahogany will be the wood of choice as it is very stable and resists the elements and insects. Why should I worry about the elements if the wood is inside the building you ask. Dampness would be the number one reason. These members should run across the inside of the building bracing walls. Also install some diagonal braces from corner to corner.
I speak from experience, having had buildings out on my railway for many years. There will be times when the building might get kicked, as we are not all as gentle as we try to be. There is also the Sun to consider. It can do more damage than any weather that might be trying to harm your villages.
I always remember the story about an argument between the Wind and the Sun. Each boasted that they could get the coat off the man walking down the road. The Wind tried first. The harder he blew, the tighter the man’s coat became. Then the Sun’s turn. Within a few minutes the man took his own coat off.