I wouldn't bet on any appreciation in a "war zone" but what you can bet on is debt pay down and cash flow. 

hi everyone,my name is Antonio M. i am from NYC. i have always been very interested in starting a career in REI. i currently work for a major insurance company doing auto damage assessment in NYC. my wife and I currently own a 2 family home. i joined this site bc i want to soak up as much information as possible. my wife and I have comfortable decently paying jobs but we are a bit burdened with college loans...our current goal is to pay off all debt so we can focus all our money into purchasing cash flow producing real estate. i hope to learn much from all of you here and soon start setting up a good future for my 19month old son. if you could take a look at my first post it would be great. https://www.biggerpockets.com/forums/12/topics/608311-newbie-have-idea-of-using-heloc-to-supercharge-my-rei-start

A cement or heavy wooden cover has always worked for me without the need to actually fill it in....but if you want to completely eliminate any risk filling it in is the only way to do that.

In this case, you will have a hard time, appraisers are evaluating residential multi family properties whether portfolio or FNMA/Freddie by Market Approach and the income approach is looked at to comply with market rents and the debt service works by a stress test on your financials globally with the subject property based on FHA, Freddie or FNMA.

My personal plan: I am conservative, I don't like debt and so "other peoples money" is a bad idea in my mind.

Can it simply be explained away or will it be viewed strictly as debt and, thus, negatively go against me?

I can tell you from experience underwriting deals for a number of institutional and semi-pro investors that they have achieved IRRs greater than 15% and yields greater than 8% in markets like San Francisco, LA, NY, and DC that advertise 4% cap rates.Markets with low cap rates typically share the following characteristics:1) Strong rent growth, driven by2) Strong population growth, driven by3) Strong job growth4) Low vacancy5) High per bed rents (lower operating costs as a percentage of total rent)6) Good property management options7) Higher quality tenants (young professionals like myself will rent in SF until their late 30s to early 40s)To achieve returns in these markets, investors buy buildings with significant value-add or development opportunities on very low to no leverage (debt), and refinancing the deal after stabilization to cash out.

Some mortgage handling companies are also registered debt collectors in the state of NC and can be frustrating when trying to get the payoff amounts when you try to sell.

Also, you know if the Navy has a fund for prior student debts that have already been incurred?

Another thing to be cognizant of is if there is debt associated with the properties.