Low down payment, while they pay your mortgage and also you can use W-2 to work on student loans. 

If you currently have high interest rates, consolidating will greatly reduce your minimum monthly payment amount.

The Landlord must attempt to get the property occupied at fair market value, and while vacant the tenant will make full monthly payments agreed in the lease until occupied.  

Withdraw it and use it as a down payment?

Then add ALL costs related to holding the property (utility costs, insurance premiums, property taxes, loan payments, etc.).Concessions: Concessions are what you give back to the buyer at closing.

-Tenant started demanding more pest inspections minutes after I start to enforce rent payment.

In the event one or two houses does become vacant and you have used leverage/debt, hopefully you've received good interest rates making your payments affordable.  

You could utilize the cash as the down payment and you would be able to purchase a nicer property.

Keep the insurance in the homeowners name (you become an additional insured), get a durable power of attorney from the homeowner, and make the payments on time!  

In 2008 this happened because banks were giving anyone and everyone a loan regardless of the credit score, down payment, or income.