Just the way you communicate with a borrower is governed by laws.Foreclosure is complicated and a long and costly process.Real estate finance is very complex.Reliable valuations cannot be derived from the Internet.Finance laws are very complex.

Say if financed at 20% down and 5.5% 30yr fix, is any rule of thumb / empirical way to derive cash flow and COC quickly?

I spend ENTIRELY too much time stressing and doing administrative tasks i.e. confirming our (ridiculous number) of monthly bill payments, fixing administrative issues deriving from issues on the part of my bill payees (constant), things of that nature.

Being in the business of" is usually defined by the degree of income derived by some activity vs investing.

I assume that all of these tenants derive all of their revenue from walk-in retail traffic.

It seems like a complete fallacy to rate something that doesn't exist yet AAA, especially when the company providing the underlying assets that derive the yield is a privately held company.

Read up on quantitative analysis , derivative and options valuation techniques, and stochastic methods.

Now ask how they derived it and what cap rate comps they used to make their purchase decision. 

I suspect this question derives from some prosaic advice repeated hundreds of times on how to rent a home..I am curious if any of you landlords actually make an effort to answer this question.(?)

If it were the tax payer making the repair and claiming nothing on the sale but placing his profits in the shop that ultimately reduced his tax liability, there could be issues of sham transactions.A sham transaction is one where the is little business purpose for profit, where the transaction is accomplished to derive some other benefit that would not have normally been conducted with an unrelated party.