i see that notes focus on cashflow as the main underwriting metric. What if appreciation and the prediction of appreciation was the metric to be used over the hold period? low cashflow high appreciation

Unfortunately having title issues is one of the reasons that sellers are sometimes willing to do seller financing simply because they know mortgage companies won't approve without proper title work and title insurance so they have to be more creative in the ways they sell but that can be risky for you as a buyer.If you do seller finance I recommend having very specific terms on HOW payments will be made and accepted and using a professional service like https://www.agecroftcapital.com/ for loan management in the case of any disputes - just my personal rec, not sponsored by BP though I do work for BP :)

Single family house will require you both to be creative and adaptable, but it is definitely possible. 

So in house loans would give me less restrictions for me to be a little more creative.

It's gone pretty bland without innovative ideas, creative financing, creative ways to advertise, success stories, all the focus is on very bland investing.

Buy BP's books on creative financing, zero down, subject to,  pre-forclosure, even short sales.   

We get primary residence loans for <10% down, we have the power of creativity, and if we're planning smart - we also have the opportunity to ride the wave of interest rates because we're much less dependent on adjustable rate loans.• If you want to get involved in syndications or passive real estate investing but you don't have enough in liquid cash for the minimum investment, you can use your retirement accounts like a self-direct IRA to do so!

The key to both of these strategies is cash and/or creativity.

Have you personally used creative financing for any of your fix and flip projects?

If it’s strictly an investment, you may need to consider conventional loans or other creative financing options.Cash Flow Analysis: Do a thorough analysis to ensure that the rental income will at least cover your mortgage, property taxes, maintenance, and vacancy periods.