A wrong decision here could be very costly so their fee is easily justified.  

You are asking for more management fees (or more personal landlording) by adding another.

The amount of debt on the duplex at the time of sale is no factor. 

@Klavish FarajAs mentioned not sure ones that will pay for the licensing - I know some if you are an existing employee and want to move up will pay for it or others may reimburse the cost or annual fees if you work for them but most won’t pay for it upfront

It will lead to less cash out of pocket even if their LTV's might appear lower than lenders who do not capitalize the interest reserve or finance settlement costs or origination fees.

Beyond maintenance a good PM software will auto assign late fees, e sign leases, have integrated applications and leasing and much more!

It's much more easy to use and you can negotiate the fee with the cleaner

Real Estate Wholesaling: Secure contracts for distressed properties at below-market prices and assign them to other investors for a fee.

Whether or not the note holder chooses to do anything depends on many factors, not the least of which is the interest rate being paid on the note I question vs the current market mortgage rate.  

Tampa Can Be a Good Option,it has great rental opportunities in neighborhoods like South Tampa, Tampa Heights, Seminole Heights, Carrollwood, and Brandon.Before buying, analyze costs like purchase price, rental income, management fees, repairs, and vacancy rates to ensure a good investment.Other Florida markets like Orlando or Jacksonville might offer similar benefits depending on your investment goals.