The true equivalent for the average Joe comparatively speaking would be to use all cash buy REI and investing.

It is clearly an income equivalent, because the monies are earmarked for housing needs only and the tenant never has their hands on the money.  

Given that, my cap rate is equivalent to my ROI.

You can use GMR if you like but that's not equivalent to yields or dividends.

One real-world aspect of IRR to keep in mind is that it assumes that any cash thrown off can be reinvested for equivalent returns (it indicates a compounded return).

They're completely different questions.First, do keep in mind that a house payment of $1500 is not equivalent to rent of $1500.

It's the equivalent of asking a BMW salesman advice on a car you can buy and then calling himself a "transportation consultant."

The furniture store is a public company but is it rated BBB- or higher by S&P or and/or the equivalent rating by Moody's? 

Consider a proposal to seller; seller makes pro forma cap rate equivalent payments OR seller makes 100% debt service until new tenants are procured for 100% occupancy or 12 months, or some combo.

I should have clarified that the numbers along the Y axis (the vertical axis) are the decimal equivalent to the percentages.