Mainly the "self sufficiency test". 

This could cost around $500 to $1,500 per unit, depending on the size and complexity of the project.Certifications: There may be additional costs for certifications (such as HERS ratings) or third-party testing to verify the energy efficiency of each unit.For a 90-unit project, you could be looking at costs in the range of:$45,000 to $135,000 for energy modeling and certification (depending on the cost per unit).For a 112-unit project, the costs would likely be:$56,000 to $168,000 for similar services.Tax Credit Calculation:If you meet the energy standards, you can claim up to $2,000 per unit.

My main goals with these initial projects are:1.Gaining valuable insights into the local market.2.Getting hands-on experience with out-of-state investing, particularly when it comes to remodels and managing from afar.3.Testing the entire BRRRR process to see if it’s the right strategy for me long-term.If all goes well, I’d love to scale up and explore multi-family projects.

For the son to qualify for the $250k exclusion, I believe he would most likely need to meet the ownership and use test, meaning he needs to own and live in the home as his primary residence for at least two of the last five years before the sale.

When analyzing properties, it's helpful to run a rental stress test to see if the deal can withstand unexpected challenges.

Seems interesting run a split test see if it works out for you.

Testing the market may get you an offer you're looking for!

Never heard of a voucher tenant being responsible for maintenance and repairs, rental licensing fees, lead testing upkeep, cap ex, reserves, book keeping and tax prep......and even if you self manage, it takes up your time and should be treated as an expense because its taking away from your ability to earn income elsewhere. 

Doing so will help you avoid capital gains tax if you decide to sell later.Second: Test it out by renting the property for a year.

I preach to everyone make a wish list, prioritize, test the software and double check.