Is it worth pursuing my landlord policy for the claims adjuster to go after their insurance or filing a lawsuit? 

Otherwise you will need their E&O information so you can file a claim and have this fixed. 

I don't know your state's laws but here in Georgia, for an abandoned vehicle there's stuff you file with the magistrate court and can acquire ownership.

I don't have a clue what that plastic or aluminum siding costs.Attached, are two files for breakdowns.

But you didn’t file tax yet for (2018), to show full your for it do you think that will be fine with the underwriter?

There need to be deadlines, agreements as to what happens if 'x' doesn't work out, etc., and hopefully an escape clause for the buyers in case a good condo comes up sold by people who actually intend to sell no matter what.Even if sellers agree to sell no matter what, there needs to be a deadline clearly specified for them to move out, it can't just be when they find a place.

While I like to put my requirements for renting (income requirements, no previous history of dispossessory filings or evictions, etc.) first in a rental ad I find many don't bother reading the ad before they respond.   

We will be filing our articles of incorporation with the Arizona corporation commission.

Since my labor is "free", the majority of costs could be bonus depreciated (LVP) separate from the building or small enough to be considered Repairs or Cleaning and Maintenance.I'll probably run my reasoning and numbers by a local REI CPA to see if anything raises red flags though before filing.

Nothing fancy, I just have a tickler file to check any of the sites like Realtor dot com about a month after the supposed closing.