Can pay a flat fee listing service... 

One suggested signing up for their service plan ($20/month per apartment) which includes one annual boiler checkup prior to the winter to avoid issues like mine and small discount on regular plumbing services (50% off of service call charge of $95 and 10% off labor costs after).Is this something you guys would recommend?

I am a Field Service Engineer, I repair/service Nuclear SPECT camera's.

The gas company employees are killing there business here.One thing you need to consider is if the house has enough power service to feed an electric hot water heater, you may have to upgrade that. 

No different than people accepting poor service at a place of business by continuing to patronize it and creating a sense of norm around accepting poor service.

Where will you get the down payments, make debt service, manage, etc?

I live in the Bay Area and work for a public home-builder as a Land Acquisition Analyst.

The property currently cash flows me about $790 per month after debt service and all expenses and the property management fee.

In VA, it's really easy and a great way to pre-screen people, it's like getting a public background check.  

Make sure it explicitly explains the process for termination if you are unhappy with their services, but especially if they violate the terms of your agreement.3.