When the IRA invests in real estate using debt not only does it have to be non-recourse but the IRS says, you can use leverage but since you aren't only using IRA money for this investment the retirement account is going to pay UBIT on the income generated because of the debt. 

If so you need to fall into the guidelines (for the investor whos funding it) regarding non arms length transactions.The most common scenarios they typically prohibit are:- Gifts of Equity- Bailouts- Leaseback OptionsAt the end of the day it needs to be a legitimate transaction, with legitimate funds coming into close.

A lot of them contain Balloon Payment Provisions. 

I know property managers in every state who use non-refundable application fees and it is the standard for every class of property and applicant.

Keep in mind of the I/O(payments/period) and game plan on how fast you'd like to pay it down. 

Your payments are known. 

Non-QM I can do things like bank statement, self-employed, ITIN, Jumbo, blah blah blah.

It might make the most sense to just sell your primary residence and use it as 40% to 50% down payment on your future home. 

do not use a line of credit for a down payment. 

Key Factors for a Good Seller-Financed DealCash Flow: Rental income should exceed monthly payments (PITI) by at least 1.25–1.5x.Purchase Price: Compare to ARV and market value for fair pricing and equity potential.Interest Rate: Aim for competitive rates; higher rates must still allow positive cash flow.Amortization/Balloon Terms: Favor longer amortization and align balloon payments with your exit strategy.Down Payment: Lower upfront costs reduce risk but should meet the seller's expectations.Flexibility: Seek no prepayment penalties and fair late-payment clauses.Property Condition: Ensure the property’s condition matches terms through inspections.Seller Motivation: Assess the seller’s willingness to negotiate favorable terms.Exit Strategy: Have a clear plan for refinancing or payoff at term end.Portfolio Fit: Ensure the deal aligns with your financial goals and risk tolerance.Vetting multiple deals and consulting professionals is crucial to making sound decisions.