I represent a number of lenders on environmental issues. if you have solvents migrating off-site, you may not only possibly become a responsible party but also could become subject to toxic tort suit for property damage. your lawyer should advise you on the wisdom of enrolling in the state brownfield or voluntary cleanup program. to maintain liability protection, you need to exercise "appropriate care". doing work pursuant to a state agreement will generally provide you with such protection. you probably wont be able to get insurance coverage for on-site cleanup but might be able to get coverage for off-site claims.

What kind of insurance do you all feel is an absolute must and what additional coverage is worth paying for (ex. loss of rent, vandalism, etc.).

I was hoping there was a standard amount of coverage/deductible (which it seems to be whatever the agent thinks is best), but actual cash value vs. replacement cost adds a totally new variable that makes it even more confusing.

You will need to rewrite the coverage to a Dwelling/FIre form (may also be called a Landlord form by some companies).

Being 1099 it can be difficult to find the right coverage.

It also means you should not have submitted an offer until you had these documents and of course have read them.You would have also received and Addendum to the Contract - Comprehensive Rider To The Residential Contract For Sale And Purchase - Part A of the disclosure states: IF THE DISCLOSURE SUMMARY REQUIRED BY SECTION 720.401, FLORIDA STATUTES, HAS NOT BEEN PROVIDED TO THE PROSPECTIVE PURCHASER BEFORE EXECUTING THIS CONTRACT FOR SALE, THIS CONTRACT IS VOIDABLE BY THE BUYER BY DELIVERING TO THE SELLER OR SELLER'S AGENT OR REPRESENTATIVE WRITTEN NOTICE OF THE BUYER'S INTENTION TO CANCEL WITHIN 3 DAYS AFTER RECEIPT OF THE DISCLOSURE SUMMARY OR PRIOR TO CLOSING, WHICHEVER OCCURS FIRST. 

I just moved and received a piece of mail for insurance coverage for just such an occasion.

Any recommendations on which companies and what type of service or coverage I should target? 

😂We use a one page contract for all of our deals.They're both comprehensive and easy to explain to homeowners.Even with a one page contract though, as @Eric H. said, it's important to actually know and understand what's in it.

Even if you are able to self insure for the replacement cost of the dwelling you should always remember that your liability exposure is limitless so for the liability reason alone you should always insure and have enough liability coverage on the policy and an umbrella policy to be safe.