I want to be seen an somebody trust-worthy, friendly, and eventually become a genuine leader, through hard work and reliability.

I know that fannie mae recently changed its guidelines about multi-family property loans, and now allows a 5% down payment for 2-4 unit homes as long as the owner will occupy one unit.

The flooring costs came out to $6000 total ($500/month) which effectively reduced their monthly payment to $1000/month. 

You could sell everything off and live off the cash.You could learn about seller financing and sell your properties over time, collecting payments each month without having to deal with tenants and toilets.Have you looked for a local investor group? 

You should certainly start the process earlier than maturity, especially at the very least within a couple months of the maturity date - there can always be things that cause delays and pushes and even missing the maturity date by a couple weeks can have harmful consequences (since it will technically be a default / missed payment even if the lender is OK with it).Also, commercial loans even with the strictest prepayment protections / lockout periods will almost always have at least a 3-month open period prior to the Maturity Date

Note:  from a "buy" standpoint, unless you are all cash/heavy down payment, today's interest rates for investors in the 6%+ range don't cut it. 

We keep a credit on our account so we can just call down and order an inspection without having to either go there or wait til they get our payment. 

Gain immediate access to all of the Bootcamp's content upon payment and review on a schedule that best fits around you.Our Self-Guided Bootcamp will feature the following courses:Being a Real Estate RookieBeing a Rookie LandlordSTR or Short-Term RentalsInvesting in Multi-Family PropertiesHouse HackingCan't wait to jumpstart your investment success?

But you may be able to take over the mortgage payment from him. 

On the other hand, a cash-out refinance of your current duplex is another avenue to explore, albeit with considerations such as the risk of losing your low 3.5% interest rate and increasing your loan amount and monthly payment, thereby reducing your current positive cash flow.