We network with other fix & flippers teaching them how to properly structure a seller financed note so that it has value on the secondary market, we then buy a partial from them to take out most, if not all, of their cost basis so they can recapitalize and go do another deal. 

Both tenants just moved out.I just got a bid to correct the foundation the right way by the most reputable company I could find (full underpinning, 60+ piers) ~$65k, plus costs of repairing drywall, paint, vacancy, and new flooring.

We did consider/evaluate that option, and have done multiple flips, but at those points have been under contract since New Year's Eve and carrying costs for another 2-3 months without a guaranteed sale is not the risk we want to assume.

If each property costs $200,000 and your only acquisition cost is a 25% down payment, you will need $850,000 (17 × $200,000 × 25%) in savings, an almost impossible amount for most people.

Can you give more details on your numbers, purchase prices, rehab costs, time to complete rehab, ARV, monthly rent?

What is the cost, and what does it cover?

At this point since it's after the fact while not totally correct; you may explore adding the missed asset/basis amount as a selling cost to just reduce your gain. 

The longer you hang out on the bridge the more it costs you.

Any reason why you need a "private person" here? 

Only reason I've been doing it is to get 0% business credit card limit increases.