And that wouldn't leave us much left for our development of our vision.  

I was wondering what is the tax treatment for that.

Once you're able to see either certified property records or tax filings, you'll see either the real expenses for the property or the fluffed expenses LL has included to get better tax treatment.  

Our ultimate vision is to get the land zoned, purchase the land and then get a construction loan to build a house on the land. 

If not already treated, even some oil or deck treatment on the deck boards would maybe lessen the gap, plus it'll prolong the life of the deck.

Here is a link to a fogger I used in the past. https://www.chewy.com/virbac-knockout-area-treatment-spray/dp/53854?

If these are simply garden variety rental properties I would think you would be in the Passive Activity element of the applicable guidance, but see below for the definition of categories and the applicable interest tracing treatment accorded to each.https://www.law.cornell.edu/cfr/text/26/1.163-8T

What kind of sewer treatment plant is it?

Usually 2-3 treatments over a 15 minute period completely resolves the issue. 

The second way is likely to be slightly better tax treatment, but your CPA can look at your overall picture and let you know which way is best.