Hi all, looking for some advice please!

About a year ago I purchased 4 homes in Detroit, each costing about $38k, all cash and they are still non-financed.  Two were originally Section 8, now only one is (tennant insisted on endless unaffordable improvements, so I had to lose the status).  

An out of state family member is currently managing them on my behalf.

Now the 3 non-section 8 are all 2-3 months behind in rent.  I understand eviction is typically a $3k process, which is almost 4 months worth of rent - not ideal.  I'm not sure offering them $800 (a months rent) in cash to leave would work, as they are effectively making that every month already.  I was also advised that leaving the property empty for any period (seems a possibility during an eviction process) runs the risk of copper pipes etc being stolen in this area.

What would you suggest?  If I regularly have to give up a quarter of annual rent to evict ppl, plus some additional missed rent, i'm not sure if these are worth the investment, even if the headline return should be 18%?  Is there an insurance that can be taken out for this?  What's the best practice in terms of how quickly you would start the eviction process given the high cost?  

Thanks so much for any advice!
Danielle