If the sewer is still functioning (sounds like it is) you get to decide what to do with the money.

If you want another layer of protection get an umbrella policy.You don't want to trigger the due on sale clause for a likely low interest mortgage.Also if you aren't operating your LLC 100% you likely only have a false sense of security. 

It looks like they are focus on the Detroit market.

Whereas we have used him before on stuff we were thinking he would be well below the other bid..

You don't have a great case for a tax appeal here because it looks like it was upped based on the renovation and improvements done prior to you buying it.

Welcome to BP community and I am new here as well.

But you still have to provide (and maintain) a kitchen, a bathroom, HVAC (well maybe just heat), a water heater.

Find something that was logged lets say 20 years ago but really well replanted. 

I agree with @Nicholas L. that the 50% rule is likely to be the more accurate indicator.   

Both are well kept, in a prime spot, with great rental demand.