With this loan, do properties have to be "Turn Key" to qualify or can they be used on fixer uppers?

If it was a community property state you could file them on Schedule E as a Qualified Joint Venture.

Key Details of the 45L Tax Credit:The credit offers up to $2,000 per eligible unit for builders and developers of residential homes that meet specific energy efficiency criteria.To qualify, the units need to meet or exceed certain energy performance levels in comparison to the national model energy code (e.g., 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.

Can your wife qualify for REPS in theory?

My though process in undercutting the bank by 1 % was to possibly attract qualified buyers.

Make it your business practice to post the notice to pay or quit precisely on the day after the grace period ends, every time.

Quote from @Tiarnan Gormley: How will you qualify for loans?

To qualify for a loan, focus on having a credit score of at least 620 (or 580 for FHA loans), keeping your total monthly debt under 43% of your income, and saving enough for a down payment and closing costs—about 5-10% of the home's price in total.

This will not qualify for 1031 Exchange treatment under the present structure and "use." 

If you go that route, ensure to use a Qualified Intermediary to handle the sale/purchase otherwise there will be no 1031 exchange.