He offered to sell it to me with owner financing for $400,000 and only required 10% down, so I jumped on it.

Credit is a factor as bad credit may limit options, or may have the lender require you to put 10 or 20 years of taxes and insurance into escrow. 

Rent control measures, burdensome employment regulations, and excessive administrative requirements exemplify this.

For MOST counties the time period is at least 3 days notice required (for your tenant to comply).  

They have 4.8 stars out of almost 1000 reviews, and the BBB gives them an A+ rating but they require 4 to 6 thousand dollars up front to work with them.

Although, some of the information was not required either time and some was required both times.

But is there a requirement that you need to full fill before making your first post?

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.

Its a great idea, but you will need to consult the township in order to understand their requirements for liveable space.

While they generated some cash flow, I found the effort required to manage them wasn’t worth the return.