This is a long shot but it just might be worth it.Best of luck.

But I'm inexperienced, so I can't just take that at face value, thinking just because it has tenants, that it'll be worth having.

Can't tell if that's worth it, although with today's rates, might just be the status quo.

I think it's worth the few extra $ to use some of the tools available.

In addition, they have had their real estate agent manipulate the MLS listing numerous time since being under contract, which we have record of.

Additionally, a deal like this (on city water/sewer) would only be worth about $330k, tops.Plus the seller is a pathological liar if he/she says their expenses are just $10,000 annually. 

Some cities like Arlington, Dallas, and Fort Worth have more.   

In some markets, a simple bedroom will bring $1,000+ per month in rent, and in other markets the same bedroom is only worth $300/mo.

If you're going upscale in other ways, you can sometimes get away with cheaper side pieces, but if the chairs are going to feature prominently in the photos and design, a few hundred extra dollars are worth it. 

You are better off with a DSCR loan and paying a little higher rate, plus a lot less risk than using all of your net worth as collateral.