Low or no down, seller financing and low or no interest with a balloon payment later is the holy grail (location, building condition, market also matter but it sounds like you have all that).

The only difference is the seller remains on title until we have enough equity to refinance or sell.3: Typically we don’t agree to balloons.

I know there's seller finance and "B" lender that are good for the short term, but if a balloon payment is due say in 5 years, there's no guarantee that my DTI would be in a better place then I'd be stuck without funding. 

The limited housing supply has resulted in increased competition among buyers and higher prices. 

Perhaps there's ample supply in Columbus Ohio but what parts of Miami?

I offered them 10% down, interest rates favorable to me, amortized for 30 years, but with a balloon payment after 3-5 years.

Here's the breakdown:Financing: We used a seller carry deal with 25% down ($100k), a 30-year term (balloon in 10 years), and a 4.68% interest rate.

Some people are sending supplies (clothes, other needed items like school supplies, food for humans and pets, etc). 

With this property I racked up some credit card debt, around 20k and I need another 20k to pay contractors/supplies.

I think 7-10yr balloon would better suit a note buyer if you go that route.