If they sell them on amazon, they likely don't require any special handling.

You’ll have 45 days from your sale to identify them and you’ll have to buy enough of them, and only them, within 180 days of your sale to meet your 1.1M requirement, or face taxes.

Simply gifting him half the property now wouldn’t immediately allow him to claim the exclusion without fulfilling this residency requirement, I don't believe.One thought would be to use a HELOC to pull just enough equity out of the current home and use it to buy a smaller home, or at least the down payment.

., the 2006 or 2009 IECC — International Energy Conservation Code).Cost Considerations for a 90-unit or 112-unit Project:The actual cost of qualifying for the 45L tax credit depends on various factors, including:Energy Efficiency Compliance: The primary cost will come from ensuring that each unit meets the required energy efficiency standards, which typically involve energy modeling, certification from third-party energy raters, and potentially upgrading insulation, HVAC systems, windows, and other components of the building to meet the necessary performance levels.Energy Modeling: Typically, you'll need to pay for an energy consultant or engineer to model the building's energy performance and ensure it qualifies for the credit.

.: Quote from @Jay Hinrichs: Let me break your post into parts, as each concerns a different subject and as such requires a different response.1.

I also require additional security deposit and sometimes a guarantor if they were approved in this manner.I also agree that this situation sounds like a pattern not a one-time mistake or short term tough situation that caused this.  

By identifying the right buyer within our network and streamlining the transaction process, we added value without requiring extensive renovations.

I highly recommend finding a broker and have them find a policy that meets your specific requirements.

Private notes require more work than Stocks / Bonds, is the added return worth the extra work?

My advice is to require them to pay the full balance upon the next payment.