AFAIK, the most you'd be on the hook for is $200 + court fees if you were to lose.

Borrower paid single premium is when the insurance company charges a lump sum at closing, rater than monthly fees that last until you hit 20% equity by amortization.

I'm assuming they would charge a fee for the renewal, so I'm surprised you didn't notice.

We are on MLS with a flat fee agent ($200 to list and comply).  

Or should I sign a contract with the investor that says he will pay me the agreed finder's fee once he does purchase?

If you're in a very competitive market you may want to get the house staged (filled with furniture) for marketing purposes.If you must list it in such a way as to disclose the address (for example you list it with an agent as a rental) please spend the extra $15-20 bucks to install a simplisafe alarm system: this is an inexpensive alarm system that works over 3G cellular networks.

Can you actually break even on a unit with a 15 year mortgage, association fees, and maintenance? 

There are gutter shields that you can install.  

After a quick conversation with the store sales associate, we realize just how simple the installation would have been had we done it ourselves.

The last thing you want to do is pay a Lender Up Front Fees, unless its for an Appraisal.You can search "DO HARD MONEY" here on the Bigger Pockets search bar, and you'll find a lot of posts reviewing their experience with DO HARD MONEY.