If your family are builders, why wouldn’t they be interested in alternative building technologies? After you build your house, maybe they will see the value of it and add that knowledge to what they do now. It might decrease the cost of alternative homes for the un-handy among us.
We are also planning on moving (from Southern California- hot, dry and crowded) and although we want a family “compound”, the relatives at this point do not want to chip in financially. That is kind of you to want to help with the family bug-out. For us, trying to buy a place that will welcome the relatives in the future is challenging.
Your decision is harder in light of the fact that we do not know what the future holds- will Winnipeg get colder, dryer, wetter? It sounds like you would be wise to move to higher drier ground if you question the infrastructure. The plains in the States have been hard-hit by massive flooding in the last few years, beyond what anyone expected.
The other issue you have is the emotional one of the impact of leaving the family. Is anyone willing to relocate with you? Maybe a brother or two if you have them-