So of I understand this correctly, that means there is very little the federal government can do besides use indirect levers to decrease cost, like:

1. Further increase immigration to ensure there are enough workers to avoid labour cost from increasing.
2. Keep driving inflation down so general costs don't get worse.
3. Resist calls for short term relief schemes which will increase prices by letting people spend more.

What else can be done at the federal level?

The big cost savings items all seem like they are Municipal and Provincial, like: getting rid of minimum parking requirements, deceasing per unit land costs, and allowing more units to be built in the communities people want to live in.