Our occupancy rates have been 65-95% during the peak.

It is the interest rates at which banks lend to each other and is short for Secured Overnight Financing Rate. 

I think they're probably paid part of the signup fee.

Should I wait for Spring for greater inventory, or for lower rates to see if cashflow improves?

As far as whether to approach them with or without an agent - approaching them directly without an agent can save the seller probably 2.5-3% of fees, which give you some room to negotiate on the price, but you need to be confident that you are capable of evaluating the property value, estimating on the amount of work that is needed, knowing how to negotiate/ structure the deal, and navigating the closing process.

They are short term loans, usually 6-12 months, high rate, interest only payments. 

Condo fees $800 a month. 

Our cash on cash return is essentially infinite as we make money on the delta between the yield of the discounted note that we purchase and the interest rate we pay to our passive private capital partners. 

Is it a viable option and what could I do to increase my success rate when taking this opportunity?

As always, make sure to run the numbers carefully and factor in local property taxes and HOA fees, which can vary widely in North Texas.Delayed gratification is key in real estate investing, but with patience, the rewards can be life-changing.Best of luck with your search