Being a realtor has limitations as all transaction are regarded as regular income (add both side is SS and regular tax rate  25 percent, instead of long term capital gains15 percent) so for me it’s the difference of 23 percent taxes versus 46 percent.

Do I form a limited partnership with an agreement specifying these details?

If this were foundation plumbing or electric I'd obviously (have to) hire a licensed contractor but this work didn't seem too... risky in being able to salvage after some loss to erroneous work or performance.

However, certain issues, such as limited partnership interests are always presumed to be securities. 

Other than coming up with 20%+ down on the full amount, how could owner financing play into this situation to limit the amount of capital required upfront?

If this is the case after a title search just get them to sign a general or limited warranty deed.

Sometimes (not always) a business has to do eat a loss - it's that bit of business that is known as risk taking.

You do have to recapture what your were entitled to take in depreciation (whether you did or not) and that is taxed at ordinary income with a limit of 25%

Is there a limit on the number of loans on a property?

It took over 18 months to recover but determination to make sure all my investors were paid in full was a priority.Needless to say, even experienced investors can take losses and those claiming they have never lost money have not done enough deals, have not been in the business long enough or are liars.Congrats to you and your accomplishment.