Not everything on Zillow is listed this is even more so on Craigslist; Redfin, Realtor.com, or an actual agent's drip will be far more accurate when looking at on market properties. 

While I don't expect an impending depression (likely no one could accurately predict the timing of one), I am just interested in being prepared against the remote possibility that we could experience a depression at some point in our lifetimes.

I have never been involved with such an elaborate scam unfortunately I pulled the short straw on the investor gamble. 

IRS requires you to track and report your properties separately so that gain/loss and locked/unlocked passive losses can be accurately captured. 

Don’t get me wrong, I like your idea, heck I’m interested if you find another deal or a small multi, but right now it seems far from a partnership and more of a one sided gamble.

The best and most accurate way is to have a realtor pull comps for you.The next best way is to look up recent sales on Realtor.com, Redfin, Zillow, etc.Make sure you look for properties that are similar in size, condition, location ,etc.You want the properties you're using as comps to be as similar to your property as possible.The best comps to use will be the CLOSED sales within the past 12 months.

I am also open to suggestion with an efficient way to find the most accurate comps 

Everything @David Sicherman stated is 100% accurate.

@Jen PothilatWithout knowing the exact location, it would be hard to give a fully accurate analysis of this property, but the asking price seems a bit high for 6 units.

Most answers you’re likely to receive will need a big ol’ “it depends” qualifier.The best, fastest, and most accurate response will come from a quick phone call to several local banks in your area!