There are several variables and it would be necessary to understand your overall financial position and goals.  

Given that there are a multitude of variable factors independent of one another driving up housing prices here I am confident property values will hold and only increase in the future.

I'm also having analysis paralysis and can't trust my own calculations (fear that I'm missing some variable or not doing the calculations correctly) during the due diligence.

There are a lot of variables here…

In effect, there is more information available to make a risk-adjusted lending decision when banks provide capital for multifamily properties.This, among two or three other major variables (recourse vs. non-recourse, GP/sponsor track record), make it easier to secure a loan on multifamily deals.

@Sean McKee The weather is too variable.

I got 90%LTV at Prime minus .51%, so 4.99% variable.  

Without reviewing the file and knowing all of the variables, it's hard to give you an exact amount, but, if title is clean and there are minimal taxes owed or tax lien - the guy might just sign over the property in a deed in lieu for you once he gets served to avoid a deficiency balance.

Determining whether to do a cost segregation study or not has a lot variables.

I've never seen or heard of any personal risk assessment mathematically but lets take a stab at just some of the variables, it's on you to weight them numerically.