Not gonna break the bank, but I think this is as clear as day -- they are responsible for that $920.However, more importantly, only two tenants (of four), were ever on the lease, and only one of the four tenants ever signed the lease.  

Titan Wealth Group is a local one, you can sign up for their investor mailing list at their website. 

What if someone sees a bandit sign/flyer in that area even though he/she lives outside of that area?

Most agents would begin the conversation by asking if you're working with another agent, and if so, they would either ask you to sign an exclusive agreement or let you and the agent work together.

You could even offer a window unit as a lease signing bonus.

Advertise rental through several streams (craigslist, sign, word of mouth, Zillow, potentially an agent depending on response rate)2. sign up for a background check service to check on prospective tenants3. cursory review of applicants4. submit a scaled-down list to background service and follow up on any referrals for potentials5.

If the property is a true FSBO, then there would not be an agent to contact, and if it is not you would put them in violation of the contract they signed with the agent.  

I signed up with a new company instead of renewing.

@Benny Gelbendorf go to the education tab and select forums.

You need to consider whether you want the parent co-signing or not.