On your balance sheet you already spent money to acquire the asset to using that asset to replenish your cash is reasonable business accounting measures.  

The supply and demand ratio can be measured from statistical analytical calculation.

CapRates are also a measure of risk. 

Alright Im a bit confused here on how much value this guest house can add to the property.So the main house is a 2 bed 1 bath 856 sq ft with a detached  1 bed 1 bath guest house is the back yard measuring at 342 sq ft.

No “DTI” Ratio – conventional lenders will require a “Debt-To-Income” ratio that measures all of your income vs. all of your expenses, and can’t qualify under a certain percentage – even if the property should make money on its own2.

Populations are moving within the city (more people downtown/in the city limits than previously), though, which I think could lead to some of the statistics you list.2) Job growth is kind of hard to measure in this area, along with population growth, because it's comprised of so many different municipalities.

For example, Del Mar passed a regulation that banned STRs in residential areas, but the Coastal Commission ruled the ban was too harsh and indicated Del Mar could not make such a stringent ban. 

Credit score is not a good measure of tenancy.

If the property is underwater, loan covenants may become more stringent, potentially triggering default provisions or additional penalties.

You made your threat, and in turn she apologized and called you "Mister," restoring you to the full measure of landlording manhood you knew you deserved.