She wants me to get the home and land but want to give the money she would receive from my down payment ($80k) and monthly payments to her estranged son’s children.

The rents will cover the home mortgage and the car payment. 

The note holder collects the remaining payments due on his note from the treasury bond coupons.6.

The seed money started as an SFR that I put $30K (hard earned savings) as a down payment.

This is how bank originated debt works in the apartment scenario you describe: The lender collects their origination fees and debt service payments are then collected priorty every month until the loan is paid off.  

From then on, I make the payments and I own the house.

We've considered private lending (secured, 1st mortgage) and are being courted by a couple real estate agents and property management companies.

You'd have to add a security system & cameras but other than that can't imagine much overhead.

One offered asking price with a $20,000 down payment and atleast a 3 year balloon.I really need to get this house sold.

Would I be able to take out a loan, let it sit in my personal savings account for at least 60 days and be able to use that as a down payment on a house?