The principal has hired an attorney years ago not sure what she has done.

i.e. single proper Buyer agreement, exclusive buyer agreement, etc.Does the principal broker her a signed agency disclosure with this party?

When you hang your license with the broker, you bring on certain liability as a salesperson, even if you're not representing any principals. 

Add in the principal paydown on the investment property which would be another 5k.

While down payments and principal payments aren't deductible, inspection fees and other acquisition costs can be added to the property’s basis for depreciation.

mortgage principal will remain in the future

Did they suffer loss of principal during down cycles (or even up cycles for that matter). 

They analyze components such as cash flow, principal paydown, appreciation (both home and renovation), initial equity, depreciation, and interest deductions for tax savings, giving you a clear picture of individual gains and ROI over 30 years.

Yeah, I get the infinite banking principal and see many others leveraging the concept. 

Maybe it’s just gut feel, but for some reason It FEELS like these two scenarios will provide excellent opportunities moving forward, while fishing for notes to purchase at significant discounts to current principal enough to yield sufficient returns doesn’t seem as promising.