I think you deleted a sentence or something. Your 5% number is to do with the opportunity cost? So you're saying that the project cost Vancouver 5% of 31.8M ie 1.6M. That makes sense.
I think comparing it to the cost of a single duplex is a good way to provide context.
But the city didn't buy the units, they only catalyzed their construction. So it's not a perfect analogy.
Another short coming of your analysis is that the estimated cost of the loan is ignoring the risk of default. What if the contractor spends the money, but fails to complete the project? Or builds it but cuts a bunch of corners and gets sued into bankruptcy?
The risk of that is the real cost of the project. But overall I like your analysis, thanks for bringing it up.
Ice cream is better imo because you're less likely to kill somebody