Other ways of using SDIRAs could be to invest in syndications, performing  or non-performing debt, precious metals, raw land, precious metals, mobile home parks, self-storage facilities and more. 

If you want the least amount of paperwork, you could consider refinancing into a debt service loan.

typically (as you probably know) you buy something distressed, with either cash or hard money, you fix it up, and then you refinance into long term debt. 

If you do have enough other income then you dont even need to lease out this property to start your refinance.However if you dont have enough income to qualify with no rental income offset then yes you will need to obtain your lease(s) and security deposit + 1st months rents deposited before you can utilize 75% of this gross income - your monthly PITIA payment (in terms of qualification on this property refinance.So all in all Id make sure what your current debt to income position is first of all (DTI) and then strategize to see if you even need the leases at all.

Also, do you have enough equity that if you sold one you could pay down most of the debt on the other 3?

Solo 401(k)s are not subject to UDFI (Unrelated Debt-Financed Income) on the capital gains from selling a debt-financed property, per IRS rules.b.

Further, the property may qualify for larger loans based on the increased cash flow ability to service debt.  

Eliminate debt, establish a budget, and save.

People carry too much debt and even if the debt was forgiven or paid off, incomes don't match affordability. 

No owner is going to care if you print a brochure or show up with index cards written in crayon.