If your loan is $110K then the payment on the 15 year would be $927/month at 6.15%; 30 year option at 6.625% would be $690.

One thing to be aware of is the FHA multifamily self-sufficiency calculation which determines if a property can generate enough rental income to cover its mortgage payments.

Have you considered tapping into your existing rental equity for the down payment?

So basically in my mind this would not be a great financial move as we be accruing about 200k more in debt if we were to sell one house and take the cash from there and use it as a down payment.

Do you need to refinance quickly to avoid a balloon payment or other financial pressure?

How will the partnership cash flow cover the HELOC payments if interest rates increase?

My goal is to offer an affordable monthly payment that competes with renting a comparable property and offers a benefit to paying a bit more to "own". 

MattIRA sells and owner finances the property for 200k and gets 30k down payment.

Use the 20K as a down payment on the next house hack and don't touch your current properties equity.

But my down payment 3 years ago is only 10% of the total price $42K.