Most serious and qualified tenants are searching on the major 3rd party platforms you mentioned + realtor.com, redfin, and a few others.Apartments.com & homes.com are owned by the same company and may offer some additional marketing options.Another strategy to consider here is social media - video marketing.

You can usually find some events by doing a simple google search.

How do you identify the sleeper deals on-market?

This allows us to underwrite the entire market simultaneously, identifying the top investments every day.

In the meantime I will continue the search for a new PMC and talk to our lawyer with the intent of filing a suit since odds are it will be needed. 

Use the search function for this one. 

You can also find real estate investing groups through meetup.com, Facebook, or a Google search.

What are the chances that someone would search this online forum, find this thread, and create an account just to make a positive comment on this thread about this company?

Not only would you benefit from having a partner's input on the deal, but you would also have an experienced individual to work alongside with as you navigate the project.It's also important to make sure you have identified your "team" ie; contractors / realtors / lenders / insurance agents / title company / etc. 

Found it on Zillow searches and my agent on the ground got me into a virtual tour quickly How did you finance this deal?