@Josh EdelsonHopefully she is amending your return at no cost if this was missed by her.Given that you have properties in MO, IN and SC may expose you to tax filing obligations in those states. 

Principal and interest payments are not a factor in cap rate.Cap rate is the Net Operating Income (NOI) divided by the property value. 

It comes down to your comfortability.With 2-4 units, you would qualify for a higher loan amount because they factor in the income from the other units.Whenever I write offers that are not accepted, I always ask for feedback as to why the other offer got accepted.  

The cap was the go-to metric 15 years ago when I started investing, now it seems way more factors come into play, such as appreciation, quality of the property (I bought something with a 22% cap in Braddock PA last year, but also the wind could blow it over at any minute...), and estimated future value increases.  

Are they doing everything they can to expose properties to the widest possible market?

Hence one of the factors driving up the acquisition price. 

It is crucial to analyze a market before you invest in it.There are various factors that you can analyze to have a thorough, multidimensional analysis of the market.

Of course land acquisition factors into this as it always does, and getting more rural = cheaper land but at cost of greater input for buildable land so I see it in many cases close to a break-even on that point.

Is it just a matter of factoring these expenses into the analysis and seeing what the monthly cash flow is like? 

I doubt inventory will be substantially up until spring and demand isn’t going anywhere, so the big factor is rates.