I do run credit & background checks that they pay for, but that is separate from just the application.

Joel has some valid points but, if you start talking about foreclosure rescue, you might want to check with the laws of your state regarding licensure requirements as a foreclosure consultant.

a lot... a ton.... off the charts.... not even close...Check real comps in area

Start checking Zillow, Redfin, etc., for both rentals and sales prices. 

A contractor can help yes when it comes to looking at it and telling you how much or what you be looking at if you want to upgrade or fix something visible but you need the inspector to check out the roof AC and plumbing thoroughly despite what it looks like in person I’ve seen mini jacked up ceilings.

I'm a licensed realtor so I have access to the local LMS, I check out public LMS sites, Facebook, Craigslist, and the few deals I find are gone far too quickly...I work a full time job and do real estate on the side.

check your local laws as a few people on BP have posted that you can only do evictions for unpaid rent in some areas.

I also open up Airbnb and/or VRBO so that I can cross-check the properties. 

They plug in their check out date and then they can log in to their streaming services and load others.

Some scammers actually have enabled their victims (tenants who call about the fake rental ads) to move into the home by breaking in and changing the locks, while the owner/seller is unaware because they aren't checking on the property.