I will come with the final points.
We need to share tax information between different levels of government. In Ontario, for example, in determining who gets reduced copays on provincial drugs, the only information the province has is on who is eligible for GIS, so they have an artificially low cut-off. To share that information better, we need to coordinate relief programs between different levels of government, federal and provincial. Just as many people don't know about GIS, many people aren't aware of provincial benefits they can access—for example, energy reduction costs.
Finally, in talking about housing, municipalities could introduce progressive property taxes to tax at a higher rate more expensive houses but offset that against earned income, so that there's a disincentive for people to invest and leave homes vacant. To do that, though, would again require government coordination.
I'll stop there, but in question period I'm happy to provide responses to the first or third question, if time permits.