Do you think risk & reward always needs to be symmetrical? 

Well, what would be happening is that your buyer would be buying your house subject to the existing note, since you can't legally sell the property without paying off that note or transferring the debt to the new buyer.

The issue is that the lender  is looking for comps for a duplex, where 2 units were packaged together and sold together, but no comps exist for that in this neighborhood since all townhomes are being built and sold individually. 

Does this exist in the commercial realm?

That begs the question are you seeing similar in your markets with either single family homes existing or new construction?

This measure is designed to shield existing homeowners from the rapid increases in property tax bills that have become a pressing concern.

Where I'm at, if you leave a tiny piece of an existing wall and rebuild the remaining 99.99%, it's a remodel instead of a new build and the property taxes don't reset. 

LLC or Land Trust vesting is never stopping the existing lender from calling the loan, in fact the opposite, it may trigger it.

Cherry-picking rehab costs won’t give you the full picture since everything ties into existing systems, permits, and infrastructure.For a garage conversion, you’re adding sqft  which means extra costs for HVAC, insulation, electrical, and possibly new windows or structural changes.

I am wondering what resources exists within BP for Canadian investors?