Minneapolis just passed a 40% property tax reduction for properties which are considered affordable: http://www.startribune.com/tax-break-will-increase...

Increasing taxes on existing landlords are just being passed on the renters.  

Getting the ADU permitted will increase the total square footage listed in the county records and increase the value of the home.

Also youMay be able to increase rents to increase performance after you get it.

Rents could be increased to 4000k without any addtl work on the property which you could estimate property value would be 230k with increased rents.

Last: the numbers are tight because of the Boston market, but i see this property continuing to increase in value over a long term (20+). 

(cheapest option)- Should I increase the actual cash value to $60k to cover current market value of my investment?

I think this is due to the sharp increase in interest rates over the last month.

Second, if the investor holds the investment in the Opportunity Fund for at least ten years, the investor would be eligible for an increase in basis equal to the fair market value of the investment on the date that the investment is sold or exchanged.Q.

Rental rates continue to outpace housing values, which means the gap between income and expenses is notably increasing.