What the investor will have is a long term appreciating asset; that will provide an increasing cash flow as rental rates increase, and steady amortization as the note is paid down.  

While less than 10% of the mortgage industry offers 40-year mortgages, here's something to factor in: they often come in with a rate increase of 20-35 bps.Assume 35 bps.$300k mortgage at 7.25% (30-year): $2,046$300k mortgage at 7.6% (40-year): $1,996Technically, it lowers the monthly, but not by much once factoring in the rate adjustment.

What is the compelling reason for them to pick you, with your competitive rates, over someone else they've already been using with competitive rates? 

Currently there is that extremely thin, hard, cheap landlord carpeting (and also an area with cheap thin stick on hard tile squares). 

Hard money loans can be an option, but they often come with high-interest rates and short repayment terms.

There are quite a number of things that can make utilizing an FHA loan more difficult such as more barriers during appraisal, appearance of low qualification/little cash, typically longer closing period, likely higher interest rate, and PMI cannot be dropped without a refinance if 3.5% down.That said, just chain 5% down conventional loans, and make sure your duplexes pay for themselves.  

You are likely overpaying by $5,000.Broker fee of $3,000 and Processing Fees of $2,000 seem out of place...but then again, i never used a broker to get a loan so I am not sure about that.If the broker was able to get you an interest rate or loan product that you wouldn't be able to find on the open market...its high, but likely fair.if you are getting a loan product that you could have gotten by going to a normal bank...seems high and unnecessary. 

This person likely has a 30-year fixed rate mortage financed at less than 4.5%. 

At any rate it is possible, but depending on your appraisal it could be a gamble

Combine that with insurance raising rates not just for dropping licensee count, but also to cover increased lawsuit risks.